HA17384

HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP High Speed Current Mode PWM Control IC for Switching Power Supply ADE-204-028A (Z) 2nd Edition Nov. 1999 Description The HA17384S/H and HA17385H are PWM control switching regulator IC series suitable for highspeed, current-mode switching power supplies. With ICs from this series and a few external parts, a small, low cost flyback-transformer switching power supply can be constructed, which facilitates good line regulation by current mode control. Synchronous operation driven after an external signal can also be easily obtained which offers various applications such as a power supply for monitors small multi-output power supply. The IC series are composed of circuits required for a switching regulator IC. That is a under-voltage lockout (UVL), a high precision reference voltage regulator (5.0 V ± 2%), a triangular wave oscillator for timing generation, a high-gain error amplifier, and as totem pole output driver circuit which directly drives the gate of power MOSFETs found in main switching devices. In addition, a pulse-by-pulse type, highspeed, current-detection comparator circuit with variable detection level is incorporated which is required for current mode control. The HA17384SPS includes the above basic function circuits. In addition to these basic functions, the H Series incorporates thermal shut-down protection (TSD) and overvoltage protection (OVP) functions, for configuration of switching power supplies that meet the demand for high safety levels. Between the HA17384 and HA17385, only the UVL threshold voltages differ as shown in the product lineup table.(See next page.) This IC is pin compatible with the “3842 family” ICs made by other companies in the electronics industry. However, due to the characteristics of linear ICs, it is not possible to achieve ICs that offer full compatibility in every detail. Therefore, when using one of these ICs to replace another manufacturer’s IC, it must be recognized that it has different electrical characteristics, and it is necessary to confirm that there is no problem with the power supply (mounting) set used. HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Functions • Under-voltage lockout system • Reference voltage regulator of 5.0 V ± 2% • Triangular wave (sawtooth) oscillator • Error amplifier • Totem pole output driver circuit (direct driving for power MOSFETs) • Current-detection comparator circuit for current mode • OVP function (over voltage protection) *1 • TSD function (thermal shut-down protection) * 1 • Protect function by zener diode (between power input and GND) Note: 1. H series only. Features • High-safety UVL circuit is used (Both VIN and Vref are monitored) • High speed operation:  Current detection response time: 100 ns Typ  Maximum oscillation frequency: 500 kHz • Low standby current: 170 µA Typ • Wide range dead band time (Discharge current of timing capacitance is constant 8.4 mA Typ) • Able to drive power MOSFET directly (Absolute maximum rating of output current is ±1 A peak) • OVP function (over voltage protection) is included *1 (Output stops when FB terminal voltage is 7.0 V Typ or higher) • TSD function (thermal shut-down protection) is included *1 (Output stops when the temperature is 160°C Typ or higher) • Zener protection is included (Clamp voltage between VIN and GND is 34 V Typ) • Wide operating temperature range:  Operating temperature: –20°C to +105°C  Junction temperature: 150°C * 2 Note: 1. H series only. 2. S series only. 2 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Product Line-up Package Additional Function TSD (Thermal shutdown protection) — r r OVP (Over voltage protection) — r r 8.4 7.6 UVL Power Supply Threshold Voltage DILP8 (DP-8) HA17384SPS HA17384HPS HA17385HPS SOP8 (FP-8DC) HA17384SRP HA17384HRP HA17385HRP VTH UVL (V) Typ 16.0 VTL UVL (V) Typ 10.0 Pin Arrangement COMP FB CS RT/CT 1 2 3 4 8 7 6 5 Vref VIN OUT GND (Top view) Pin Function Pin No. 1 2 3 4 5 6 7 8 Note: Symbol COMP FB CS RT/CT GND OUT VIN Vref Function Error amplifier output pin Inverting input of error amp./OVP input pin Current sensing signal input pin Timing resistance, timing capacitance connect pin Groung pin PWM Pulse output pin Power supply voltage input pin Reference voltage 5V output pin 1 Note 1. Overvoltage protection (OVP) input is usable only for the HA17384H and HA17385H. 3 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Block Diagram 0.8mA UVL1 COMP 1 H 5V band gap reference regulator UVL2 OVP latch RQ S 7 TSD sense 160°C CS latch OR 34V 2R R 1V VIN 8 Vref − + EA 6.5V 1 2 Vref (2.5V) L VL VH FB (OVP input) 2 − OVP + *1 7.0V 2VF Vref > 4.7V − CS 3 NOR OUT Totem pole output circuit 6 OUT + CS R S Q PWM LOGIC Vref Oscillator + RT/CT 4 − 1.2V 2.8 V Latch set pulse 5 GND 8.4 mA Note: 1. Blocks with bold line are not included in HA17384SPS/SRP. 4 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Absolute Maximum Ratings Item Supply voltage DC output current Peak output current Error amplifier input voltage COMP terminal input voltage Error output sink current Power dissipation Operating temperature Junction temperature Symbol VIN IO I O PEAK VFB VCOMP I OEA PT Topr Tj Rating 30 ±0.1 ±1.0 –0.3 to VIN –0.3 to +7.5 10 680 –20 to +105 125 150 Storage temperature Tstg –55 to +125 –55 to +150 Unit V A A V V mA mW °C °C °C °C °C 3 4 3 4 1, 2 Note Notes: 1. For the HA17384HPS and HA17385HPS, This value applies up to Ta = 43°C; at temperatures above this, 8.3 mW/°C derating should be applied. For the HA17384SPS, This value applies up to Ta = 68°C; at temperatures above this, 8.3 mW/°C derating should be applied. 800 Power Dissipation PT (mW) 680mW 600 HA17384SPS HA17384HPS, HA17385HPS 400 374mW 200 166mW 43°C 68°C 105°C 120 125°C 140 150°C 160 0 −20 0 20 40 60 80 100 Ambient Temperature Ta (°C) 5 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Absolute Maximum Ratings (cont) Notes: 2. This is the value when the device is mou nted on a glass-epoxy substrate (40 mm × 40 mm × 1.6 mm). However, For the HA17384HRP and HA17385HRP, Derating should be performed with 8.3 mW/°C in the Ta ≥ 43°C range if the substrate wiring density is 10%. Derating should be performed with 11.1 mW/°C in the Ta ≥ 63°C range if the substrate wiring density is 30%. For the HA17384SRP, Derating should be performed with 8.3 mW/°C in the Ta ≥ 68°C range if the substrate wiring density is 10%. Derating should be performed with 11.1 mW/°C in the Ta ≥ 89°C range if the substrate wiring density is 10%. HA17384SRP : −11.1 mW/°C (wiring density is 30%) : −8.3 mW/°C (wiring density is 10%) HA17384HRP, HA17385HRP : −11.1 mW/°C (wiring density is 30%) : −8.3 mW/°C (wiring density is 10%) 800 Power Dissipation PT (mW) 680 mW 600 500 mW 400 374 mW 222 mW 200 166 mW 0 −20 43°C 20 63°C 68°C 89°C 105°C 120 125°C 140 150°C 160 0 40 60 80 100 Ambient Temperature Ta (°C) 3. Applies to the HA17384HPS/HRP and HA17385HPS/HRP. 4. Applies to the HA17384SPS/SRP. 6 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (The condition is: Ta = 25°C, VIN = 15 V, CT = 3300 pF, RT = 10 kΩ without notice) Reference Part Item Reference output voltage Line regulation Load regulation Output short current Temperature stability Output noise voltage Symbol Vref Regline Regload los ∆ Vref VN Min 4.9 — — –30 — — Typ 5.0 20 10 –100 80 100 Max 5.1 50 25 –180 — — Unit V mV mV mA ppm/°C µV Test Condition Io = 1 mA 12 V ≤ VIN ≤ 25 V –1 mA ≥ Io ≥ –20 mA Vref = 0V Io = –1 mA, –20°C ≤ Ta ≤ 105°C 10 Hz ≤ fnoise ≤ 10 kHz 1 1 Note Notes: 1. Reference value for design. Triangular Wave Oscillator Part Item Typical oscillating frequency Maximum oscillating frequency Supply voltage dependency of oscillating frequency Temperature dependency of oscillating frequency Discharge current of CT Low level threshold voltage High level threshold voltage Triangular wave amplitude Symbol fosc Typ fosc Max ∆ fosc 1 ∆ fosc 2 Isink CT VTLCT VTHCT ∆ VCT Min 47 500 — — 7.5 — — — Typ 52 — ±0.5 ±5.0 8.4 1.2 2.8 1.6 Max 57 — ±2.0 — 9.3 — — — Unit kHz kHz % % mA V V V ∆ VCT = VTHCT – VTLCT 12 V ≤ V IN ≤ 25 V –20°C ≤ Ta ≤ 105°C VCT = 2.0 V 1 1 1 1 Test Condition CT = 3300 pF, RT = 10 kΩ Note Notes: 1. Reference value for design. 7 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (cont) Error Amplifire Part / OVP Part Item Non-inverting input voltage Input bias current Open loop voltage gain Unity gain bank width Power supply voltage rejection ratio Output sink current Output source current High level output voltage Low level output voltage OVP latch threshold voltage OVP (FB) terminal input current OVP latch reset V IN voltage Note: Symbol VFB I IB AVOL BW PSRR I Osink EA I Osource EA VOH EA VOL EA VOVP I FB(OVP) VIN(OVP RES) Min 2.42 — 65 0.7 60 3.0 –0.5 5.5 — 6.0 — 6.0 Typ 2.50 –0.2 90 1.0 70 9.0 –0.8 6.5 0.7 7.0 30 7.0 Max 2.58 –2.0 — — — — — 7.5 1.1 8.0 50 8.0 Unit V µA dB MHz dB mA mA V V V µA V 12 V ≤ V IN ≤ 25 V VFB = 2.7 V, VCOMP = 1.1 V VFB = 2.3 V, VCOMP = 5.0 V VFB = 2.3 V, RL = 15 kΩ(GND) VFB = 2.7 V, RL = 15 kΩ(Vref) Increase FB terminal voltage VFB = 8.0 V Decreasing VIN after OVP latched 1 1 1 Test Condition VCOMP = 2.5 V VFB = 5.0 V 2.0 V ≤ V O ≤ 4.0 V Note 1. These values are not prescribe to the HA17384SPS/SRP because OVP function is not included. 8 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (cont) Current Sensing Part Item Voltage gain Maximum sensing voltage Power supply voltage rejection ratio Input bias current Current sensing response time Symbol AVCS Vth CS PSRR I BCS tpd Min 2.85 0.9 — — 50 Typ 3.00 1.0 70 –2 100 Max 3.15 1.1 — –10 150 Unit V/V V dB µA ns 12 V ≤ V IN ≤ 25 V VCS = 2 V Time from when VCS becomes 2 V to when output becomes “L” (2 V) 3 2 Test Condition VFB = 0 V Note 1 Notes: 1. The gain this case is the ratio of error amplifier output change to the current-sensing threshold voltage change. 2. Reference value for design. 3. Current sensing response time tpd is definded a shown in the figure 1. Vth VCS VOUT (PWM) tpd Figure 1 Definition of Current Sensing Response Time tpd PWM Output Part Item Output low voltage 1 Output low voltage 2 Output high voltage 1 Output high voltage 2 Output low voltage at standby mode Rise time Fall time Maximum ON duty Minimum ON duty Symbol VOL1 VOL2 VOH1 VOH2 VOL STB tr tf Du max Du min Min — — 13.0 12.0 — — — 94 — Typ 0.7 1.5 13.5 13.3 0.8 80 70 96 — Max 1.5 2.2 — — 1.1 150 130 100 0 Unit V V V V V ns ns % % Test Condition losink = 20 mA losink = 200 mA losource = –20 mA losource = –200 mA VIN = 5 V, losink = 1 mA CL = 1000 pF CL = 1000 pF 1 1 Note Notes: 1. Pulse application test 9 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (cont) UVL Part Item Threshold voltage for high V IN level Threshold voltage for low VIN level VIN UVL hysteresis voltage VHYS UVL VTL UVL Symbol VTH UVL Min 14.5 7.6 9.0 6.8 5.0 0.6 Vref UVL threshold voltage VT Vref 4.3 Typ 16.0 8.4 10.0 7.6 6.0 0.8 4.7 Max 17.5 9.2 11.0 8.4 7.0 1.0 Vref Unit V V V V V V V Voltage is forced toVref terminal Test Condition Turn-ON voltage when VIN is rising Minimum operating voltage after turn-ON VHYS UVL = VTH UVL – VTL UVL Note 1 2 1 2 1 2 Notes: 1. For the HA17384S/H. 2. For the HA17385H. Total Characteristics Item Operating current Standby current Current of latch Power supply zener voltage Overheat protection starting temperature Notes: 1. 2. 2. 4. Symbol I IN I STBY I LATCH VINZ TjTSD Min 7.0 120 200 31 — Typ 10.0 170 270 34 160 Max 13.0 230 340 37 — Unit mA µA µA V °C Test Condition CL = 1000 pF, VFB = VCS = 0 V Current at start up VFB = 0 V after VFB = VOVP I IN + 2.5 mA 3, 4 1, 2 Note These values are not prescribe to the HA17384SPS/SRP because OVP function is not included. VIN = 8.5 V in case of the HA17384H. These values are not prescribe to the HA17384SPS/SRP because TSD function is not included. Reference value for design. 10 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Timing Chart Signal Name Power ON IC turn ON Stationary operation Input voltage VIN Pin 7 0V 2V 16 V (8.4 V) Waveform timing (Outline) OVP input OVP latched condition 10 V (7.6 V) Power OFF Reset of OVP latch 7.0 V 2V This voltage is determined by the transformer UVL1 Internal signal which cannot be externally monitored. Reference voltage Vref Pin 8 UVL2 Internal signal which cannot be externally monitored. Oscillation voltage of triangular wave RT/CT Pin 4 Start up signal Internal signal which cannot be externally monitored. PWM latch setting signal internal signal which cannot be externally monitored. Error amplifier input signal VFB Pin 2 ( ) shows the case using HA17385H 0V 5V 0V 4.7 V 4.7 V 0V 2.8 V 0V IC operates and PWM output stops. 0V 1.2 V Start up latch release 0V 7.0 V typ (OVP input) 0V VCOMP Error amplifier output signal 0V VCOMP Pin 1 ID *1 OVP latch signal Internal signal which cannot be externally monitored. PWM output voltage VOUT Pin 6 0V VIN 0V ID Note: 1. ID indicates the power MOSFET drain current; it is actually observed as voltage VS generated by power MOSFET current detection source resistance RS. VCOMP indicates the error amp output voltage waveform. Current mode operation is performed so that a voltage 1/3 that of VCOMP is the current limiter level. 11 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Operation (Description of Timing Chart) From Power ON to Turn On After the power is switched ON, the power supply terminal voltage (VIN) of this IC rises by charging through bleeder resistor RB. At this time, when the power voltage is in the range of 2 V to 16 V*1 . The low-voltage, lock out UVL1 operates and accordingly the OUT voltage, that is, the gate voltage of the power MOSFET, is fixed at 1.3 V or a lower value, resulting in the power MOSFET remaining in the OFF state. When the power supply voltage reaches 16 V, UVL1 of this IC is reset and the reference voltage (Vref) generating part turns ON. However, until Vref becomes 4.7 V, the low-voltage, lock out UVL2 operates to keep the OUT terminal voltage low. After Vref terminal voltage becomes 4.7 V or higher, OUT terminal outputs a PWM pulse. Note: 1. The value is for the HA17384S/H. The value is 8.4 V for the HA17385H. Generation of Triangular Wave and PWM Pulse After the output of the Vref, each blocks begins to operate. The triangular wave is generated on the RT/CT terminal. For PWM pulses, the triangular wave rise time is taken as the variable on-duty on-time. The triangular wave fall time is taken as the dead-band time. The initial rise of the triangular wave starts from 0 V, and to prevent a large on-duty at this time, the initial PWM pulse is masked and not output. PWM pulses are outputted after the second triangular wave. The above operation is enabled by the charge energy which is charged through the bleeder resistor RB into the capacitor CB of VIN. Stationary Operation PWM pulses are outputted after the second wave of the triangular wave and stationary operation as the switching power supply starts. By switching operation from ON/OFF to OFF/ON in the switching device (power MOSFET), the transformer converts the voltage. The power supply of IC VIN is fed by the back-up winding of the transformer. In the current mode of the IC, the current in the switcing device is always monitored by a source resistor R CS. Then the current limiter level is varied according to the error voltage (COMP terminal voltage) for PWM control. One third of the error voltage level, which is divided by resistors “2R” and “R” in the IC, is used to sense the current (R = 25 kΩ ). Two diodes between the error output and the 2R-R circuit act only as a DC level shifter. Actually, these diodes are connected between the 2R-R circuit and GND, and, the current sensing comparator and GND, respectively. Therefore, these blocks operate 1.4 V higher than the GND level. Accordingly, the error of the current sensing level caused by the switching noise on the GND voltage level is eliminated. The zener diode of 1 V symbolically indicates that the maximum sensing voltage level of the CS terminal is 1 V. 12 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Power OFF At power OFF, the input voltage of the transformer gradually decreases and then VIN of IC also decreases according to the input voltage. When V IN becomes lower than 10 V*2 or Vref becomes lower than 4.7 V, UVL1 (UVL2) operates again and the PWM pulse stops. Note: 2. The value is for the HA17384S/H. The value is 7.6 V for the HA17385H. Commercial AC voltage − + − 100µ 200V RB 220k 1/4W HRP32 P CB 10µ 50V + − B S Power switch Line filter 20k + Rectifier bridge diode VIN SBD ex. HRP24 + + − 1000µ 10V DC output − OVP input (Ex: from photocoupler) 3.6k 0.1µ COMP 150k RT 10k 100p FB CS RT/CT CT 3300p VCS 330p 1k VIN 51 OUT GND Vref Floating ground Power MOSFET ex. 2SK1567 HA17384H, HA17385H RCS 1 2W Figure 2 Mounting Circut Diagram for Operation Expression 13 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 2R 1V − VCS CS terminal + CS R 2VF CS latch R S Q PWM pulse VCOMP COMP terminal (Error output) Latch setting pulse (Implemented in triagular wave oscillator) Latch setting pulse VCOMP Error voltage VCS Current sensing level ×13 Figure 3 Operation Diagram of Current Sensing Part Current Sense Comparator Threshold Voltage VCS (V) Point: 1) At maximum rated load, the setting should be made to give approximately 90% of area A below. 2) When the OVP latch is operated, the setting should be made in area B or C. 1.0 B Heavy load 0.8 0.6 A 0.4 Light load 0.2 C 0.0 0 1 2 3 4 5 6 7 Error Amplifier Output Voltage Vcomp (V) 8 1.4V 4.4V 7.5V A : Stationary operation / PWM (Current-mode operation) B : Current limit operation / Max duty cycle C : No sensitivity area / No PWM output Figure 4 Current Sense Characteristics 14 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Features and Theory of Current Mode Control Features of Current Mode Control • Switch element current detection is performed every cycle, giving a high feedback response speed. • Operation with a constant transformer winding current gives a highly stable output voltage (with excellent line regulation characteristics, in particular). • Suitable for flyback transformer use. • External synchronous operation is easily achieved. (This feature, for example, is applicable to synchronization with a forizontal synchronizing signal of CRT monitor.) Theory of Current Mode Control In current mode control, a PWM pulse is generated not by comparing an error voltage with a triangular wave voltage in the voltage mode, but by changing the current limiter level in accordance with the error voltage (COMP terminal in this IC, that is,output of the error amplifier output) which is obtained by constantly monitoring the current of the switching device (power MOSFET) using source resistor R CS. One of the features of current mode control is that the current limited operates in all cycles of PWM as described by the above theory. In voltage mode, only one feedback loop is made by an output voltage. In current mode, on the other hand, two loops are used. One is an output voltage loop and the other is a loop of the switching device current itself. The current of the switching device can be controlled switch high speed. In current mode control, the current in the transformer winding is kept constant, resulting in high stability. An important consequence is that the line regulation in terms of total characteristics is better than that in voltage mode. AC input OSC S Flip flop R RS Transformar DC output Current sense comparator + − 2R R IS − VCOMP + Error amplifier Vref Figure 5 Block Diagram of Current Mode Switching Power Spply 15 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP A. Control in the case of heavy load VCS IS B. Control in the case of light load VCS IS As the load becomes heavy and the DC output decreases, the current sensing level is raised as shown in A. above in order to increase the current in the switching device in each cycle. When the load decreases, inverse control is carried out as shown in B. above. Figure 6 Primary Current Control of Transformer in Current Mode (Conceptual Diagram) 16 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Main Characteristics Supply Current vs. Supply Voltage (HA17384S/H) 20 Operating Current IIN (mA) Operating Current IIN (mA) Ta = 25°C fosc = 52kHz CT = 3300pF RT = 10kΩ Supply Current vs. Supply Voltage (HA17385H) 20 Ta = 25°C fosc = 52kHz CT = 3300pF RT = 10kΩ 15 15 10 Latch current (HA17384H) 10 5 5 Latch current 0 0 10 20 30 Power supply voltage VIN (V) 40 0 0 10 20 30 Power supply voltage VIN (V) 40 Standby Current/Latch Current vs. Supply Voltage Exploded diagram of the small current part from the above figure (HA17384S/H) Standby Current/Latch Current vs. Supply Voltage Exploded diagram of the small current part from the above figure (HA17385H) 2.0 Operating Current IIN (mA) 1.5 Operating Current IIN (mA) Ta = 25°C 2.0 Ta = 25°C 1.5 1.0 Latch current (HA17384H) 1.0 Latch current 0.5 0.5 0 0 10 20 30 Power supply voltage VIN (V) 40 0 0 10 20 30 Power supply voltage VIN (V) 40 Operating Current vs. Ambient Temperature Standby Current/Latch Current vs. Ambient Temperature 12 Standby ⋅ Latch Current (µA) Operating Current IIN (mA) VIN = 15V fosc = 52kHz CT = 3300pF RT = 10kΩ 400 Latch current VIN = 15V (HA17384H) VIN = 8.5V (HA17385H) 11 300 10 200 9 100 Stanby current 8 −20 0 20 40 60 80 Ambient temperature Ta (°C) 105 0 −20 0 20 40 60 80 Ambient temperature Ta (°C) 105 17 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP UVL Threshold Voltage vs. Ambient Temperature 20 HA17384S/H Line Regulation Characteristics of Reference Voltage 5.2 Reference voltage Vref (V) Ta = 25°C CT = 3300pF VIN = 10V or more (HA17384S/H) RT = 10kΩ VIN = 7.6V or more (HA17385H) UVL voltage (V) 15 VTH VTL HA17385H 5.1 10 VTH VTL 5.0 5 4.9 0 −20 4.8 0 20 40 60 Ambient temperature Ta (°C) 85 0 10 20 Supply voltage VIN (V) 30 Load Regulation Characteristics of Reference Voltage 6.0 Reference voltage Vref (V) Reference voltage Vref (V) Ta = 25°C VIN = 15V CT = 3300pF RT = 10kΩ Reference Voltage vs. Ambient Temperature 5.2 VIN = 15V CT = 3300pF RT = 10kΩ 5.5 5.1 5.0 Vref short protection operates 5.0 4.5 4.9 4.0 0 20 40 60 80 100 Output current of Vref terminal (mA) 4.8 −20 0 20 40 60 80 Ambient temperature Ta (°C) 105 CT discharge current ICT (mA) Ta = 25°C VIN = 15V CT discharge current IsinkCT (mA) CT Discharge Current vs. RT/CT Terminal Voltage 9.5 Measured when RT/CT terminal voltage is externally supplied CT Discharge Current vs. Ambient Temperature 9.5 VIN=15 V 9.0 9.0 8.5 Minimum voltage of triangular wave Maximum voltage of triangular wave Measured when RT/CT terminal voltage of 2 V is externally supplied 8.5 8.0 8.0 7.5 0 1 2 3 RT/CT terminal voltage VCT (V) 4 7.5 −20 0 20 40 60 80 Ambient temperature Ta (°C) 105 18 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 500 Oscillation frequency fosc (kHz) Ta = 25¡C VIN = 15V 200 100 50 20 10 5 500 F 0p 47 = pF CT 00 F 10 00p F 22 00p µF 47 01 F 0. 2µ 02 F 0. 7µ 04 0. 1k 2k 5k 10k 20k 50k 100k 200k Timing resistance RT (Ω) Triangular wave PWM maximum ON pulse Du max = 95% fosc = 52kHz In the case of small CT and large RT (ex. CT = 3300pF, RT = 10kΩ) Triangular wave PWM maximum ON pulse Du max = 40% fosc = 52kHz In the case of large CT and small RT (ex. CT = 0.033µF, RT = 680Ω) 19 Figure 7 Oscillation Frequency vs. Timing Resistance Case 1. Setting large maximum duty cycle. Case 2. Setting small maximum duty cycle. Figure 8 Relationship Between Triangular Wave and Maximum ON Duty of PWM Pulse HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 100 Maximum ON duty Du max (%) Ta = 25°C VIN = 15V 75 50 25 0 500 1k 2k 5k 10k 20k 50k 100k 200k Timing Resistance RT (Ω) Note: In the oscillation system of this IC, a constant discharging current of 8.4mA flows the timing capacitor during triangular wave fall. Therefore, note that a small maximum ON duty (large dead band) leads to a large supply current. Refer to the equations of oscillation frequency and supply current for details. Figure 9 PWM Pulse ON Duty vs. Timing Resistance 20 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Oscillation Frequency vs. Ambient Temperature 65 Operating Current IIN (mA) VIN = 15V CL = 1000pF Oscillation Frequency fosc (kHz) Operating Current vs. Maximum ON Duty 25 VIN = 15V Ta=25°C 20 fos 60 55 50 45 40 −20 C = 0.033µF Dumax = 40% RT = 680Ω T C = 3300pF Dumax = 95% RT = 10kΩ T CL = 1000pF c=3 15 fos 00 VCS = 0V VFB = 0V kH z 10 5 0 0 c=5 0kH z 0 20 40 60 80 Ambient Temperature Ta (°C) 105 25 50 75 100 Maximum ON Duty Du max (%) Rise/Fall Time of Output Pulse vs. Load Capacitance 250 VIN = 15V VCS = 0V 200 VFB = 0V Ta = 25°C CT = 3300pF RT = 10kΩ Rise/Fall Time of Output Pulse vs. Ambient Temperature 250 VIN = 15V VCS = 0V 200 VFB = 0V CL = 1000pF Rise/Fall Time (ns) Rise/Fall Time (ns) 150 100 50 0 0 Rise tim e tr 150 100 50 0 −20 Rise time tr Fall Time tf CT = 3300pF RT = 10kΩ Fa me ll Ti tf 1000 2000 3000 4000 Output load capacitance CL (pF) 0 20 40 60 80 Ambient temperature Ta (°C) 105 Current Sensing Level vs. Ambient Temperature 1.25 Current sensing level VCS (V) 1.00 0.75 0.50 0.25 0 −20 VIN = 15V Measured when COMP terminal VFB = 0V voltage is externally supplied Relationship Between Low Voltage Malfunction Protection and PWM Output VIN (UVL1) Vref (UVL2) PWM OUTPUT L L L H L L H H Available to output L H L IC is in the ON Condition Standby state and Operation Standby state description state output is state fixed to LO. 0 20 40 60 80 Ambient temperature Ta (°C) 105 21 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 100 75 Phase Φ (deg) Gain AVO (dB) 50 Gain AVO 25 0 −25 Phase Φ Phase margin at fT ΦO = 60° Typ 100 1k 10k 100k 1M Error Amplifier Input Signal Frequency f (Hz) Unit gain frequency fT = 1MHz Typ 0 60 120 180 10M VIN = 15V, Ta = 25°C 10 Figure 10 Open Loop Gain Characterisrics of Error Amplifier 22 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP •Calculation of operation parameters 1. Maximum ON duty Du max (Refer to the right figure.) 1 Du max = 190Ω 1 + 1.78 × In 1 + RT − 440Ω Triangular wave ( ) 2. Oscillation frequency fosc fosc = CT × RT × { 0.56 + In (1 + R 1904Ω Ω )} − 40 T 1 PWM maximum ON pulse From the above two equations, the following two equations are obtained. 3. Equalization to device RT from Du max RT = e 190Ω 0.56 (1/Du max − 1) + 440Ω −1 (e = 2.71828.base of natural logarithm) Dumax is the ratio of maximum ON time of PWM to one cycle time. In the above case, Dumax = 95% 4. Equation to device CT from fosc and RT Du max CT = 1.78 × fosc × RT 5. Operating current IIN IIN = IQ + IsinkCT × (1 − Du max) + Ciss × VIN × fosc providing that IQ = 8.4mA Typ (Supply current when oscillation in IC stops.) Ciss is the input gate capacitance of the power MOSFET which is connected and VIN is the supply voltage of the IC. Example 1: Calculation when RT = 10kΩ and CT = 3300pF fosc = 52kHz, Du max = 95%, IIN = 9.7mA Example 2: Calculation for 50% of Du max and 200 kHz of fosc RT = 693Ω, CT = 6360pF, IIN = 12.5mA However, Ciss = 1000pF, VIN = 18V Note that the actual value may differ from the calculated one because of the internal delay in operation and input characteristics of the POWER MOS FET. Check the value when mounting. Additionally a small Dumax leads to a large supply current, even if the frequency is not changed, and start up may become difficult. In such a case, the following measure is recommended. (1) For an AC/DC converter, a small bleeder resistance is required. (2) The large capacitance between Vref and GND is required. (3) Use a large Dumax with a triangular wave and raise the current limit of the switching device to around the maximum value (1.0V Typ). V The current limit is expressed as IDmax = THCS RCS Figure 11 Calculation of Operation Parameters 23 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Application Circuit Example (1) Rectifier bridge diode + 141V + − Commercial AC 100V Line filter 20k 3.6k 10k 2SA1029 HA17384H, HA17385H 0.1µ COMP 10k RT 10k 150k 100p FB CS RT/CT CT 3300p 470p 1k VIN 51 OUT GND 1k Vref 100µ 200V 220k 1/4W HRP32 P 10µ 50V + − B SBD 1000µ HRP24 10V + S + − DC 5V, 3A OUTPUT − 16.4V VIN − Transformer specification example EI-22 type core (H7C18 × 06Z) Gap length lg = 0.3mm 2SK1567 Transformer coil example P: 0.5¿80T/570µH S: 0.5¿16T Bifiler/22µH B: 0.2¿44T/170µH 1 2W 47k HA17431 Notes: 1. : PRIMARY GND, : SECONDARY GND. 2. Check the wiring direction of the transformer coil. 3. Insert a snubber circuit if necessary. 4. OVP function is not included in HA17384SPS/SRP. Snubber circuit example 470p 1kV FRD DFG1C8 51 P S (Opetation Theory) Because this circuit is a flyback type, the voltages in the primary (P), secondary (s) coils of the transformer and backup (B) coil are proportional to each other. Using this, the output voltage of the backup coil (VIN of IC) is controlled at constant 16.4V. (The voltage of the point divided by resistors of 20kΩ and 3.6kΩ is 2.5V). Figure 12 Primary Voltage Sensing Flyback Converter 24 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Application Circuit Example (2) When the error amplifier is used − Rectifier bridge diode + 141V + − Commercial AC 100V 2SA1029 10k 47k HA17431 Line filter 10k VIN 16.4V HRP32 10µ 50V P +B − 100µ 200V 220k 1/4W SBD HRP24 S Transformer specification example EI-22 type core (H7C18 × 06Z) Gap length lg = 0.3mm Transformer coil example P: 0.5¿80T/570µH S: 0.5¿16T Bifiler/22µH B: 0.2¿44T/170µH + 330 3.3µ + − 3.3k DC 5V, 3A OUTPUT + 1.8k − 1000µ 10V B 4.7k HA17384H, HA17385H COMP 150k 100p FB RT 10k CS RT/CT CT 3300p 470p 1k VIN OUT GND 1k 1 2W 2SK1567 51 4.7k Vref 0.1µ HA17431 − Photocoupler (for output control) When the error amplifier is not used OVP input Bleeder resistor (adjuster according to the rating of the Photocoupler) COMP FB CS RT/CT Vref 0.8mA VIN OUT GND (Operation Theory) On the secondary side (S) of the flyback converter, error amplification is carried out by a shunt regulator and photocoupler. The voltage of the backup coil (B) is not monitored, which differs from the application example (1). In addition, OVP operates on the secondary side (S) using a photocoupler. Refer to the application example (1) for the other notes. Figure 13 Secondary Voltage Sensing Flyback Converter 25 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Application Examples for Fuller Exploitation of Power Supply Functions A number of application examples are briefly described below. 1. Soft start A soft start is a start method in which the PWM pulse width is gradually increased when the power supply is activated. This prevents the stress on the transformer and switch element caused by a rapid increase in the PWM pulse width, and also prevents overshoot when the secondary-side output voltage rises. The circuit diagram is shown in figure 14. VIN 7 DIN IO 800µA typ FB 2 2.5V (3V) IC internal circuit (around error amp.) 2R R (1V) 1V To power supply detection comparator CST − + EA (4.4V) Vref 5V 8 VREF (5V) D2 (3.7V) 1 RCU COMP D1 External circuit (only partially shown) Figure 14 Circuit Diagram for Soft Start Operation: In this circuit, error amp output source current IO (800 µA typ.) gradually raises the switch element current detection level, using a voltage slope that charges soft start capacitance C ST. When the voltage at each node is at the value shown in parentheses in the figure, the soft start ends. The soft start time is thus given by the following formula: TST = (3.7 V/800 µA) × CST ≈ 4.62 CST (ms) (CST unit: µF) External parts other than CST operate as follows: • Diode D1 : Current detection level shift and current reverse-flow prevention. • Diode D2 : Together with diode DIN in the IC, CST charge drawing when power supply falls. • Resistance RCU : For CST charge-up at end of soft start. (Use a high resistance of the order of several hundred kΩ.) Note: During a soft start, since PWM pulses are not output for a while after the IC starts operating, there is a lack of energy during this time, and intermittent mode may be entered. In this case, the capacitance between Vref and GND should be increased to around 4.7 µF to 10 µF. 26 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 2. OVP latch output overvoltage protection (the HA17384H and HA17385H only) The OVP latch is incorporated in the error amp input pin (FB). If the FB pin is pulled up to 7.0 V typ. just once when the power supply enters any kind of error state, IC operation can be halted and held as it is (latched). To reset the latch, drop the IC’s supply voltage to 7.0 V typ. or below momentarily. An OVP latch application example is shown in figure 15. VIN R3 10k 2SA1029 − + 2.5V EA Error amplifier 1k FB 2 1 COMP R1 R2 10k 47k HA17431 (Vref ≈ 2.5V) External circuit (only partially shown) 7.0V − OVP + OVP comparator Inside IC Figure 15 Example of OVP Latch Application Circuit This circuit protects the system by causing latch operation in the event of an overload or load short. In the steady state, the error amp input/output pins operate at 2.5 V typ., but if the load becomes heavy the FB pin level drops and the COMP pin level rises. As shown in the figure, this is detected by the HA17431 shunt regulator, and the FB pin level is pulled up, operating the OVP latch. The operation parameters are as follows: COMP pin voltage detection level: Vth = (R1 + R2) / R2 × 2.5 V 27 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Notice for Use 1. OVP Latch Block • Case When DC power is applied directly as the power supply of the HA17384H, HA17385H, without using the transformer backup coil. Also, when high-frequency noise is superimposed on the V IN pin. • Problem The IC may not be turn on in the case of a circuit in which V IN rises quickly (10 V/100 µs or faster), such as that shown in figure 16. Also, the OVP latch may operate even though the FB pin is normally at VOVP or below after the IC is activated. • Reason Because of the IC circuit configuration, the timer latch block operates first. • Remedy (counter measure) Take remedial action such as configuring a time constant circuit (RB, C B) as shown in figure 17, to keep the VIN rise speed below 10 V/100 µs. Also, if there is marked high-frequency noise on the V IN pin, a noise cancellation capacitor (C N) with the best possible high-frequency characteristics (such as a ceramic capacitor) should be inserted between the V IN pin and GND, and close to the VIN pin. When configuring an IC power supply with an activation resistance and backup winding, such as an AC/DC converter, the rise of VIN will normally be around 1 V/100 µs, and there is no risk of this problem occurring, but careful attention must be paid to high-frequency noise. Also, this phenomenon is not occuring to the HA17384S, because OVP function is not built-in. Input Output VIN VIN HA17384 Series GND Feedback Figure 16 Example of Circuit with Fast VIN Rise Time 28 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Input Time constant circuit VIN 18V CB 1µF + RB 51Ω VIN HA17384 Series GND CN Feedback Output Figure 17 Sample Remedial Circuit 2. Externally Synchronized Operation • Case When, with a power supply using the HA17384S/H or HA17385H, externally synchronized operation is performed by applying an external syncronous signal to the RT /CT pin (pin 4). • Problem Synchronized operation may not be possible if the amplitude of the external syncronous signal is too large. • Reason The RT /CT pin falls to a potential lower than the ground. • Remedy (counter measure) In this case, clamping is necessary using a diode with as small a VF value as possible, such as a schottky barrier diode, as shown in figure 18. Vref HA17384 Series RT CT 47 0.01µF External synchronous signal Figure 18 Sample Remedial Circuit 29 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Package Dimensions Unit: mm 9.6 10.6 Max 8 5 6.3 7.4 Max 1 0.89 4 1.3 2.54 Min 5.06 Max 1.27 Max 7.62 0.1 Min 0.25 – 0.05 0° – 15° Hitachi Code JEDEC EIAJ Mass (reference value) + 0.10 2.54 ± 0.25 0.48 ± 0.10 DP-8 Conforms Conforms 0.54 g Unit: mm 4.90 5.3 Max 5 8 3.95 1 4 *0.22 ± 0.03 0.20 ± 0.03 1.75 Max 0.75 Max 6.10 – 0.30 + 0.10 1.08 0° – 8° + 0.67 + 0.11 0.14 – 0.04 1.27 *0.42 ± 0.08 0.40 ± 0.06 0.60 – 0.20 0.15 0.25 M *Dimension including the plating thickness Base material dimension Hitachi Code JEDEC EIAJ Mass (reference value) FP-8DC Conforms — 0.085 g 30 HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Cautions 1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent, copyright, trademark, or other intellectual property rights for information contained in this document. Hitachi bears no responsibility for problems that may arise with third party’s rights, including intellectual property rights, in connection with use of the information contained in this document. 2. Products and product specifications may be subject to change without notice. Confirm that you have received the latest product standards or specifications before final design, purchase or use. 3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However, contact Hitachi’s sales office before using the product in an application that demands especially high quality and reliability or where its failure or malfunction may directly threaten human life or cause risk of bodily injury, such as aerospace, aeronautics, nuclear power, combustion control, transportation, traffic, safety equipment or medical equipment for life support. 4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly for maximum rating, operating supply voltage range, heat radiation characteristics, installation conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other consequential damage due to operation of the Hitachi product. 5. This product is not designed to be radiation resistant. 6. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document without written approval from Hitachi. 7. Contact Hitachi’s sales office for any questions regarding this document or Hitachi semiconductor products. Hitachi, Ltd. Semiconductor & Integrated Circuits. Nippon Bldg., 2-6-2, Ohte-machi, Chiyoda-ku, Tokyo 100-0004, Japan Tel: Tokyo (03) 3270-2111 Fax: (03) 3270-5109 URL NorthAmerica : http:semiconductor.hitachi.com/ Europe : http://www.hitachi-eu.com/hel/ecg Asia (Singapore) : http://www.has.hitachi.com.sg/grp3/sicd/index.htm Asia (Taiwan) : http://www.hitachi.com.tw/E/Product/SICD_Frame.htm Asia (HongKong) : http://www.hitachi.com.hk/eng/bo/grp3/index.htm Japan : http://www.hitachi.co.jp/Sicd/indx.htm For further information write to: Hitachi Semiconductor (America) Inc. 179 East Tasman Drive, San Jose,CA 95134 Tel: (408) 433-1990 Fax: (408) 433-0223 Hitachi Europe GmbH Electronic components Group Dornacher Straβe 3 D-85622 Feldkirchen, Munich Germany Tel: (89) 9 9180-0 Fax: (89) 9 29 30 00 Hitachi Europe Ltd. Electronic Components Group. Whitebrook Park Lower Cookham Road Maidenhead Berkshire SL6 8YA, United Kingdom Tel: (1628) 585000 Fax: (1628) 778322 Hitachi Asia Pte. Ltd. 16 Collyer Quay #20-00 Hitachi Tower Singapore 049318 Tel: 535-2100 Fax: 535-1533 Hitachi Asia Ltd. Taipei Branch Office 3F, Hung Kuo Building. No.167, Tun-Hwa North Road, Taipei (105) Tel: (2) 2718-3666 Fax: (2) 2718-8180 Hitachi Asia (Hong Kong) Ltd. Group III (Electronic Components) 7/F., North Tower, World Finance Centre, Harbour City, Canton Road, Tsim Sha Tsui, Kowloon, Hong Kong Tel: (2) 735 9218 Fax: (2) 730 0281 Telex: 40815 HITEC HX Copyright ' Hitachi, Ltd., 1998. All rights reserved. Printed in Japan. 31