SR037

SR036/SR037 SR036 SR037 Inductorless, Dual Output Off-Line Regulators Features ❑ Accepts peak input voltages up to 700V ❑ Operates directly off of rectified 120V AC or 230V AC ❑ Integrated linear regulator ❑ Minimal power dissipation General Description The Supertex SR036 and SR037 are inductorless, dual output off-line controllers, providing up to 1.0W of output power. They do not require any transformers, inductors, or high voltage input capacitors. The input voltage, HV IN, is designed to operate from an unfiltered full wave rectified 120V or 230V AC line. It is designed to control an external N-channel MOSFET or IGBT. When HV IN is less than 45V, the external transistor is turned-on allowing it to charge an external capacitor connected to VSOURCE. An unregulated DC voltage will develop on V SOURCE. Once HVIN is above 45V, the transistor is turned off. The maximum gate voltage for the external transistor is 24V. The unregulated voltage is approximately 18V. The SR036 also provides a regulated 3.3V whereas the SR037 provides a regulated 5.0V. WARNING!!! Galvanic isolation is not provided. Dangerous voltages are present when connected to the AC line. It is the responsibility of the designer to assure adequate safeguards are in place to protect the end user from electrical shock. ❑ No high voltage capacitors required ❑ Up to 1.0W output power ❑ No transformers or inductors required Applications ❑ 3.3V or 5.0V power supplies ❑ White goods ❑ Appliances ❑ SMPS house keeping power supplies ❑ Small off-line low voltage power supplies ❑ Lighting controls SR03x Typical Application Circuit ed nd e m om igns! ec tR o es N D ew rN Fo ~18V Unregulated GN2470 1.0µF 470µF Surge Protection Gate 120VAC or 230VAC HVIN SR036 or SR037 VSOURCE VOUT SR036: VOUT = 3.3V Regulated SR037: VOUT = 5.0V Regulated 1.0µF B092005 B092005 1 SR036/SR037 Ordering Information VOUT 3.3V 5.0V Package Options MSOP-8 SR036MG* SR037MG* SO-8 w/ Heat Slug SR036SG SR037SG * Product supplied on 2500 piece carrier tape reel. Absolute Maximum Ratings* VIN, High Voltage Input VOUT, Low Voltage Output Storage Temperature Soldering Temperature Power Dissipation, MSOP-8 Power Dissipation, SO-8 slug * All voltages are referenced to GND. 1. When underside plate soldered to 2cm2 of exposed copper. *Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground. Pin Configuration +700V HVIN 1 2 3 4 8 7 6 5 Gate Source VOUT N/C +6.0V -65°C to +150°C +300°C 300mW 1.50W1 N/C N/C GND MSOP-8 (top view) HVIN N/C N/C GND 1 2 3 4 8 7 6 5 Gate Source VOUT N/C SO-8 Slug Make no electrical connections to Backside Plate (top view) Electrical Characteristics (Over operating supply voltages unless otherwise specified, TA=0°C to +125°C) Symbol HVIN VTH VGS VGATE VOUT ∆VOUT Freq Input voltage HVIN voltage when Gate is pulled to ground Gate to source clamp voltage Gate to ground clamp voltage Regulated output voltage for the SO-8 with heat slug VOUT load regulation Input AC frequency 40 SR036 SR037 40 ±10 18 2.97 4.5 45 ±15 20 3.30 5.00 20 Parameter Min Typ Max 700 407 50 ±20 24 3.63 5.50 120 100 Units V V V V V mV Hz VSOURCE = 10V VSOURCE = 10V VSOURCE = 10V, ILoad = 0 to 50mA (1) IGS = ±100µA Conditions Peak transient voltage Peak rectified AC voltage (1) Load current on the regulated output must not cause SR03 power dissipation to exceed max ratings. Worst case power dissipation is given by: P≈ VIN 2 + (16V − VOUT ) × I OUT 185kΩ Where IOUT is the load on the regulated output 2 B092005 SR036/SR037 Typical Performance Curves Gate Clamp 25 60 HVIN (off) 20 50 40 Vgate (V) HVIN (V) -40 -10 20 50 80 110 140 15 30 10 20 5 10 0 0 -40 -10 20 50 80 110 140 Temperature (°C) Regulator Output (SR037) 6 20 18 5 16 14 Temperature (°C) Gate Voltage VGate (V) 0 5 10 15 20 25 4 VOUT (V) 12 10 8 3 2 6 4 2 1 0 0 0 10 20 30 40 50 60 70 80 Source Voltage (V) HV Input Current 2100 125 ° C 1800 5.00 25 ° C -40 ° C 4.95 4.90 4.85 4.80 600 4.75 4.70 4.65 0 50 100 150 200 250 300 350 400 0 10 5.05 HVIN (V) Load Regulation (SR037) 1500 1200 IIN (µA) 900 VOUT (V) Source=15V 25 ° C Source=8V 25 ° C 300 0 20 30 40 50 HVIN (V) B092005 IOUT (mA) 3 SR036/SR037 Applications Information Functional Block Diagram Operating Principle The SR03x operates by controlling the conduction angle of the external MOSFET or IGBT as shown in Figure 1. When the rectified AC voltage is below the VTH threshold, the pass transistor is turned on. The pass transistor is turned off when the rectified AC is above HVIN(off). Output voltage (Vunreg) decays during the periods when the switch is off and when the rectified AC is below the output voltage. The amount of decay is determined by the load and the value of C1. Since the switch only conducts with low voltages across it, power dissipation is minimized. HVIN VREF CM Gate Source Reg VOUT GND Switch ON HVIN V TH VREG not to scale VUNREG Figure 1: Typical Waveforms Power Dissipation Power dissipation in the SR03 is from 2 sources. The first is due to the bias current (or overhead) required to operate the device. This may be calculated from PBIAS = VIN2 / 185ký where VIN is the input voltage in VRMS. The second source of power dissipation is the 3.3/5V linear regulator and may be calculated from PREG = (16V - VOUT) * IREG, where VOUT is 3.3V or 5V, and IREG is the load current on the 3.3/5V output. The total power dissipated by the SR03x is the sum of these two: PBIAS + PREG. (These equations are conservative – actual dissipation may be less.) To adequately dissipate the power, the underside plate of the SR03xSG should be soldered to at least 2cm2 of exposed copper area on the PCB. Power is also dissipated by the pass transistor. Power dissipated by the transistor will be (16V * ITOTAL) * (1/Eff -1) where ITOTAL is the sum of the load currents on the regulated and unregulated outputs and Eff is the converter efficiency (see Efficiency Graph next page). The transistor should be soldered to at least 5cm2 of exposed copper area on the PCB for heatsinking. Transformers 4 B092005 SR036/SR037 Using a MOSFET in place of an IGBT VN2460 1.0µF Gate ~18V Unregulated 270µF Surge Protection 120VAC or 230VAC HVIN SR036 or SR037 VSOURCE VOUT SR036: VOUT=3.3V Regulated SR037: VOUT=5.0V Regulated 1.0µF SRO3 Efficiency SR03 Efficiency 50 VN2460, no EMI GN2470, no EMI Efficiency (%) 40 30 VN2460, w/EMI GN2470, w/EMI 20 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 PUNREG (W) Efficiency and EMI Test Circuit 120/230VAC 50/60Hz GN2470 P6KE 400CA EMI Suppressor RG 180kΩ VIN GATE SOURCE VREG VREG CREG 1.0μF CG 220pF 1.0μF VUNREG 220μF (VN2460) 470μF (GN2470) SR03x GND B092005 5 SR03 Circuit using VN2460 (with EMI Suppression Circuit) SR036/SR037 6 B092005 SR03 Circuit using GN2470 (no EMI Suppressor) 120VAC/60Hz Limits per 47CFR15.107 for Class B devices. 50mA total load. Hot Neutral SR036/SR037 Average Quasi-peak 208VAC/60Hz (230VAC/50Hz not available). Limits per CISPR 14-1 for household appliances. 25mA total load. Hot Neutral Average B092005 Quasi-peak 7 SR03 Circuit using GN2470 (no EMI Suppressor) 120VAC/60Hz Limits per 47CFR15.107 for Class B devices. 100mA total load. Hot Neutral SR036/SR037 Average Quasi-peak 8 B092005 Applications Information, continued GN2470 1.0µF SR036/SR037 Fuse VUNREG 220µF Surge Protection 120VAC or 230VAC 1KΩ Gate HVIN Source VOUT SR036 or SR037 GND VREG 1.0µF ON/OFF TN2106K1 Figure 2: Example Circuit with Enable Control Figure 2 is an example circuit using the SR036 or SR037 along with a Supertex GN2470 IGBT to generate an unregulated voltage of approximately 18V and a regulated voltage of 3.3V for the SR036 or 5.0V for the SR037. The combined total output current is typically 50mA. The TN2106K1 in series with a 1Ký resistor can be added for applications requiring an enable control. Fuse Surge Protection GN2470 1.0µF 2N3904 220µF 10KΩ 1.0MΩ Vz 5.6V Vout1 = 5.0V 1.0µF 120VAC or 230VAC Gate HVIN Source V OUT SR036 GND Vout 2 = 3.3V 1.0µF Figure 3: Generating Two Regulated Voltages For applications requiring two regulated voltages, an inexpensive discrete linear regulator can be added to regulate the unregulated output as show in Figure 3. The discrete linear regulator consists of a Zener diode, a resistor and a bipolar transistor. The regulated voltage, Vout1, is determined by the Zener diode voltage minus the base-to-emitter voltage drop of 0.6V. Figure 3 uses a 5.6V Zener diode to obtain a 5.0V output. Different Zener diode voltages can be used to obtain different regulated output voltages. B092005 9 SR036/SR037 Applications Information, continued Fuse GN2470 Unregulated Voltage 1.0µF Surge Protection 120VAC or 230VAC 220µF 1N4001 Gate HVIN Source VOUT 3.3V 1.0µF SR036 GND Logic Control Circuit 12V Coil Relay VN2110K1 Figure 4: Driving 12V Relay Coils The circuit shown in Figure 4 uses the SR036 to supply a regulated 3.3V for the logic control circuitry while the unregulated voltage is used to drive a 12V relay coil. The operating voltage for a 12V relay coil is typically very wide and can therefore operate directly from the unregulated line. Fuse Surge Protection GN2470 Unregulated Voltage 1.0µF 120VAC or 230VAC 220µF 1N4001 Gate HVIN Source VOUT SR037 GND 5.0V 1.0µF Logic Control Circuit 1KΩ 2N3904 100Ω 5V Coil Relay Figure 5: Driving 5V Relay Coils The circuit shown in Figure 5 uses the SR037 to supply a regulated 5.0V for the logic control circuitry while the unregulated voltage is used to drive a 5.0V coil relay. To overcome the voltage variation of the unregulated line, a bipolar transistor is used to drive the coil with a constant current. The resistor value from the emitter to ground sets the desired coil current. For an arbitrary coil current of 40mA, the resistor value can be calculated as: 10 B092005 SR036/SR037 Applications Information, continued Fuse GN2470 Unregulated Voltage 1.0µF Surge Protection 120VAC or 230VAC 220µF Vz 5.1V 5V Coil Relay Gate HVIN Source VOUT SR037 GND 5.0V 1.0µF Logic Control Circuit Figure 6: Driving 5V Relay Coils with Zener Diode Clamp The circuit shown in Figure 6 uses the SR037 to supply a regulated 5.0V for the logic control circuitry. A 5.1V Zener diode is used in parallel with the 5.0V relay coil to ensure that the relay coil’s maximum operating voltage is not exceeded. The Zener diode also acts as the catch diode when the coil is switched to the off state. An external series resistor is used to limit the amount of Zener current. Fuse GN2470 Unregulated Voltage 1.0µF Surge Protection 220µF 120VAC or 230VAC Gate HVIN Source VOUT SR036 or SR037 GND VREG 1.0µF 330Ω 330Ω Figure 7: Driving LEDs from 120VAC The circuit shown in Figure 7 uses the SR036 or SR037 to drive 12 high efficiency red LEDs from an AC line. The average LED current is approximately 20mA. B092005 11 SR036/SR037 Applications Information, continued Vunreg = Vz + 14V = VLED + 8V Fuse GN2470 1.0µF + 47µF R = Vunreg / 1.5mA Vunreg + Surge Protection AC line 220pF 180K EMI Filter (optional) R VLED ILED Gate HVIN Source +8V Supertex SR037 GND Figure 8: Precision current drive for LED String from AC Line Features: 1. Precision Current Regulator 2. Zener Voltage Boost 3. PWM Dimming (optional) 4. EMI Filter (optional) PWM Dimming (optional) Constant Current Regulator Iled = 2.5V / Rs < 40mA The circuit uses the SR037or SR036 and GN2470 to drive a string of LEDs from AC power line. The LED current is regulated at up to 40mA. The LED string voltage can be up to AC line voltage (120V for 120Vac / 230V for 230VAC). Vunreg = VLED + 8V < Vz + 16V Fuse GN2470 1.0µF TL431 Zener Voltage Boost 10K Vz R = Vunreg / 1.0mA Vunreg + 100µF Rs +2.5V + VLED Surge Protection AC line 220pF 180K EMI Filter (optional) R ILED Gate HVin Supertex SR037 GND Source 220nF 100k Figure 9: Simple current drive for LED String from AC Line Features: 1. Simple Current Regulator 2. Automatic Voltage Boost 3. Zener Boost Voltage Limit (optional) 4. EMI Filter (optional) Vz Zener Boost Voltage Limit (optional) + Vbe - Rs Simple Current Regulator Iled = Vbe / Rs < 40mA The circuit uses the SR037 or SR036 and GN2470 to drive a string of LEDs from AC power line. The LED current is regulated at up to 40mA. The LED string voltage can be up to AC line voltage (120V for 120Vac / 230V for 230VAC). 12 B092005 8-Lead MSOP Package Outline (MG) 0.116 ± 0.004 (2.946 ± 0.102) D SR036/SR037 B 0.013 ± 0.005 (0.330 ± 0.127) H 0.193 ± 0.006 (4.902 ± 0.152) E 0.118 ± 0.004 (3.000 ± 0.102) Full Circle, or Half Circle, 0.040 ± 0.003 A (1.016 ± 0.076) 12° ± 4° 3.0° ± 3° A1 e C L 0.004 ± 0.002 (0.102 ± 0.051) 0.0256 BSC (0.650) 0.006 ± 0.0003 (0.152 ± 0.0076) 0.0215 ± 0.006 (0.546 ± 0.152) 8-Lead MSOP (with heat slug) Package Outline (SG) 0.1935 +/- 0.0035 (4.915 +/- 0.085) 0.1 +/- 0.01 (2.54 +/- 0.25) Heat Slug 0.1535 +/- 0.0035 (3.9) (+/- 0.09) 0.236 +/- .008 (5.995) (+/- 0.205) 0.0165 +/- 0.0035 (0.42 +/- 0.09) 0.14 +/- 0.01 (3.555 +/- 0.255) 0.055 +/- 0.005 (1.395 +/- 0.125) 0.0085 +/- 0.0015 (0.215 +/- 0.035) 0.05 +/- 0.01 (1.27 +/- 0.25) 0.0575 +/- 0.0065 (1.46 +/- 0.16) 0.0015 +/- .0025 (0.065 +/- 0.035) 0.033 +/- 0.017 (0.84 +/- 0.43) Measurement Legend = Dimensions in Inches (Dimensions in Millimeters) DOC #: DSFP-SR036SR037 B092005 13 www.supertex.com 1235 Bordeaux Drive • Sunnyvale • CA • 94089 • Telephone (408) 744-0100 • Fax (408) 222-4895 Technical Bulletin: SR03x Plate Connections This bulletin applies to the SR036 and SR037 in the SG (Power SO-8) package. Increased efficiency and lower no-load power consumption of SR03x based regulator circuits can be achieved by assuring no electrical connections are made to the underside plate on the SR03x package. A copper area should still be employed to provide needed heat sinking, however, this copper area should be electrically floating. For maximum heat sinking capability, do not cover the copper area with solder mask. Existing PCB layouts with the plate grounded should be corrected. Make no electrical connections to copper area Solder underside plate to copper area for heat sinking Early SR03x demo boards erroneously had the underside plate connected to ground. These boards will exhibit decreased efficiency and higher no load power. New, corrected demo boards may be ordered from Supertex’s web site. 28APR03 www.supertex.com 1235 Bordeaux Drive · Sunnyvale · CA · 94089 · Telephone (408) 744-0100 · Fax (408) 222-4895 Technical Bulletin: SR03x EMI Reduction SR03-based power supplies may create conducted EMI into the AC power line that exceeds FCC and CISPR requirements. This bulletin describes one technique to reduce EMI, allowing SR03-based supplies to comply with applicable requirements. Conducted EMI is largely due to the short, high-current pulse imposed on the AC line when the pass MOSFET turns on. Smoothing out this current pulse reduces the harmonic content of the current drawn from the AC line, thus reducing conducted EMI. Placing a simple RC filter before the MOSFET gate smoothes out the pulse. EMI Suppressor Circuit VN2460 VUNREG P6KE 400CA EMI Suppressor RG 180kΩ VIN GATE SOURCE VREG VREG CREG 1µF CG 220pF CUNREG 220µF 120/230VAC 50/60Hz SR03x GND The values for R G and CG may need adjustment depending on the characteristics of the chosen MOSFET and the value of CUNREG. (Higher values of CUNREG generally produce higher EMI as capacitor recharge times are shorter.) The idea is to select values of R and C to soften the edges of the current pulse, as shown below. It may be tempting to forego C G, relying instead on the MOSFETs’ input capacitance. However, high dV/dt when power is first applied may cause the MOSFET to turn on due to CRSS, damaging the FET. C G protects against this possibility. Note that extending the turn-off time at the rising edge of the rectified AC increases the voltage drop across the FET, decreasing efficiency somewhat. AC Line Current – Turn-off Edge Without EMI Suppressor 500mA/div With EMI Suppressor Technical Bulletin: SR03x EMI Reduction The following spectrums show the effect of the EMI suppression technique. 120VAC/60Hz Limits per 47CFR15.107 for Class B devices. 45mA total load. Hot Neutral Average 208VAC/60Hz Quasi-peak (230VAC/50Hz not available) Limits per CISPR 14-1 for household appliances. 20mA total load. Live Neutral Average Quasi-peak Technical Bulletin: SR03x EMI Reduction The EMI reduction technique has an effect on power supply performance, as illustrated in the following graphs. 120VAC/60Hz Efficiency 19 18 17 50% Load Regulation Efficiency 40% VUNREG without EMI suppressor with EMI suppressor 16 15 14 13 12 11 without EMI suppressor with EMI suppressor 10 20 30 40 50 60 30% 20% 0 10 20 30 40 50 60 IUNREG (mA) 10 0 IUNREG (mA) 208VAC/60Hz (230VAC/50Hz not available) Efficiency 40% 18 17 16 Load Regulation Efficiency VUNREG 30% without EMI suppressor with EMI suppressor 15 14 13 12 11 without EMI suppressor with EMI suppressor 20% 10% 0 10 20 30 10 0 10 20 30 IUNREG (mA) IUNREG (mA) SR03x Technical Bulletin SR03x Power On Surge Protection When power is first applied to an SR03x circuit near the peak of the input sine wave, there is an instantaneous step of voltage at the HVIN terminal. The same step is applied to the pass element (MOSFET or IGBT). The parasitic capacitances in the pass element (MOSFET or IGBT) form a voltage divider circuit that applies an attenuated step to the gate of the pass element in the direction to turn on the pass element. If the input step voltage is large enough, the pass element will be turned on. The high impedance gate drive of the SR03x is not strong enough to shut down the pass element in time. The pass element will conduct high current while there is a large voltage across it. This over heats the pass element and destroys it. In turn, the SR03x is also destroyed. It has been reported that this power-on circuit destruction occurs frequently on 230VAC inputs and occasionally on 120VAC inputs. The protection circuit, shown below, controls the gate drive and clamps the current through the pass element to approximately 3 Amperes (exact current not critical). This allows the SR03x enough time to shut down the pass element. As shown in the circuit diagram, the surge protection requires only a resistor and a low cost NPN transistor (MPSA06 or equivalent). Power On Surge Protection Circuit Diagram A110204