CP3800
Switching Regulator Power Controller
Features
• Wide supply voltage operating range: 1.8 to13 V • Low current consumption: Typically 5.5 mA in operation, 1 µA or less in stand-by • High speed operation is possible: Maximum 1 MHz • The error amplifier gain is set inside the IC, so peripheral components are minimized. • Incorporates a soft start circuit. • Incorporates a timer-latch type short circuit detection circuit (SCP). • Totem-pole type output with adjustable on/off current (for NPN transistors) • Incorporates a stand-by function.
General Description
The CP3800 is a single-channel switching regulator control IC for low voltage applications incorporating a soft start function and short circuit detection function. The device has a low minimum operating voltage of 1.8 V and is ideal for the power supply of battery-operated electronic equipment. The CP3800 can be operated on two types: noninsulated input/output choppers (step-up, stepdown , and insulated input/output converters (flyback). The former type is used for DC/DC converters and the latter type is used for DC/DC converts and line-operation-type power supplies.
Applications
• Power source for battery-powered equipment • Power source for cameras, camcorders, VCRs, PDAs, electronic data banks, and hand-held Communication equipment
Block Diagram
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 1 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Pin Configuration
Ordering Information
CP3800 X X
Package N: DIP-8 S: SOP-8 T: TSSOP-8 Packing BLANK: TUBE A: TAPING
Pin Description
Pin No. Symbol I/O Description
1 2 3 4 5 6 7 8
INSCP VCC BR/CTL OUT GND OSC FB
I — — I O — — O
Error amplifier inverting input pin Soft start and SCP setting capacitor connection pin Power supply pin Output current setting and control pin Totem-pole type output pin Ground pin Capacitor and resistor connection pin for setting the oscillation frequency Error amplifier output pin
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 2 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Absolute Maximum Ratings
(Ta=+250C)
Parameter Power supply voltage Output source current Output sink current Allowable dissipation Operating temperature Storage temperature ESD Classification
Symbol VCC IO+ IOPD PD TOP Tstg
Condition — — — SOP-8, Ta ≦+25°C TSSOP-8, Ta ≦+25°C — — MIL-STD-883
Rated Value Min. Max. — 3 — -50 — 50 — 570 — 430 -30 +85 -55 +125 Class 2
Unit V mA mA mW mW 0 C 0 C
* : When mounted on a 10 cm square double-sided epoxy board
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.
Recommended Operating Conditions
(Ta=+250C)
Parameter
Symbol
Values
Unit
Min. Typ. Max. Power supply voltage VCC 1.8 -12.0 V Error amplifier input voltage VI -0.2 -1.0 V BR/CTL pin input voltage VBR -0.2 -VCC V Output source current IO+ -20 --mA Output sink current IO--40 mA SCP pin capacitance CPE -0.1 -μF Phase compensation capacitance CP -0.1 -μF Output current setting resistance RB 150 390 5000 Ω Timing resistance RT 1.0 3.0 10.0 kΩ Timing capacitance CT 100 270 10000 pF Oscillation frequency fOSC 10 500 1000 kHz Operating temperature TOP -30 +25 +85 °C WARNING: Recommended operating conditions are normal operating ranges for the semiconductor device. All the device’s electrical characteristics are warranted when operated within these ranges. Always use semiconductor devices within the recommended operating conditions. Operation outside these ranges may adversely affect reliability and could result in device failure.
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 3 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Electrical Characteristics
(VCC=+2V, Ta=+250C)
Parameter Circuit to prevent malfunction at low input voltage (U.V.L.O.) Soft start Short circuit detection (S.C.P.) Sawtooth wave oscillator (OSC) Reset voltage Threshold voltage Charging current Voltage at soft start completion Charging current Threshold voltage Oscillation frequency Frequency input Stability Frequency variation with temperature Input threshold Voltage VT input stability VT variation with Temperature Input bias current Voltage gain Frequency bandwidth Maximum output voltage range Output source current Output sink current Maximum duty cycle
Symbol VR VTH ICS Vts ICPC VtPC fOSC fdV fdT VT VTdV VTdT IB AV BW VOM+ VOM_ IOM+ IOM_ TDUTY VOH1 VOH2 VOL1 VOL2
Condition
Values Min. Typ. Max. --0.9
Unit V V μA V μA V kHz % % mV mV %
-VSCP=0V -VSCP=0V -RT=3.3kΩ, CT=270pF VCC=2V to 12V Ta =-300C to 850C VFB = 450mV VCC=2V to 12V Ta = -300C to 850C VIN = 0V -AV = 0 dB --
1.1 -1.5 0.7 -1.5 0.7 400 --480 ---
1.3 -1.0 0.8 -1.0 0.8 500 2 5 500 5 1
1.5 -0.7 0.9 -0.7 0.9 600 10 -520 20 --
Error amplifier
VFB = 450mV RT=3.3kΩ, CT=270pF fOSC = 500KHz RB= 390Ω, IO= -15 mA RB= 750Ω, VCC = 1.8V IO= -10 mA RB= 390Ω, IO= -15 mA RB= 750Ω, VCC = 1.8V IO= -10 mA RB= 390Ω, VO = 0.9V RB= 390Ω, VO = 0.3V --
Idle period adjustment section
-1.0 -0.2 70 100 -6 0.78 0.87 -- 0.05 --40 24 40 75 -1.0 0.8 ---30 20 1.2 1.0 0.1 0.1 -30 60 30
1.0 μA 145 V/V -- MHz -V 0.2 V -24 μA -- μA 85 % --0.2 0.2 -20 -40 V V V V mA mA kΩ
Output voltage Output section
Output source current Output sink current Pull down resistance
IO+ IORO
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 4 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Output current Setting section/ Control section Entire device
Pin voltage Input off condition Input on condition Pin current range Stand-by current Average supply current
VBR IOFF ION IBR ICCS ICC
0.10 0.19 0.25 V -20 -0 μA ---45 μA -1.8 --0.1 mA BR/CTL pin open or --1 μA VCC RB= 390,VCC =2~12V -5.5 10.0 mA RB= 390Ω --
Timing Chart
FB pin voltage Reference input for short circuit detection comparator Idle period setting voltage Sawtooth wave output Soft start setting voltage
OUT pin waveforms
SCP pin waveforms
t PE Output short circuit
Soft start tS
ON Power supply control SW OFF
Output short circuit
Short circuit detection
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 5 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 6 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 7 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 8 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 9 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 10 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Typical Application Schematic
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 11 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 12 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 13 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Functional Description
Soft Start SCP
Figure 1 Soft-Start SCP Equivalent circuit At power-on, the CP3800 operates in the soft-start mode. Since no current is supplied, comp1, comp2, and SCP latch are inactive. Immediately after power-on, the CPE capacitor is charged at a constant current of 1µA to increase from 0V. In the soft-start mode, the VSCP (capacitor CPE voltage) is input to the PWM comparator, so that the soft-start circuit is controlled at the on-duty ratio of 0% with the increase of the VSCP. When the VSCP reaches 0.8V, the soft-start supplies current to comp1, comp2, and SCP latch and at the same time discharges the CPE capacitor (VSCP=0V). This changes the soft-start mode to the normal mode (output short circuit detection wait state) and the SCP becomes active (stays low). In the normal mode, the input from the soft-start circuit to the PWM comparator is kept at 0.8V. If the switching regulator output suddenly drops due to load effect, the error amplifier output (FB pin) is fixed at VOM+ and capacitor CPE starts charging. When the voltage at the SCP pin reaches approximately 0.8V, the output pin is set low and the SCP pin stays low. Set time by the following expressions (see Timing Chart): Soft-Start time (The time until the output ON duty reaches approximately 50%)
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 14 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
t S = 0.35 × CPE ( µF )
Short-circuit detection time(or Soft-Start full time) :
t PE = 0.8 × CPE ( µF )
Setting Oscillating Frequency The oscillation frequency of a sawtooth waveform is determined by the timing capacitor (CT) and the timing resistor (RT) which are connected to the OSC pin. When the voltage of the OSC pin falls to 0.1V, the CT is rapidly charged to increase the voltage of the OSC pin instantaneously. When the voltage of the OSC pin reaches 0.8V, Charging stops, so that CT and RT are discharged to decrease the voltage of the OSC pin. The waveform of the OSC pin is shown as Figure 2.
Figure 2 Oscillator Waveform The cycle (T) can be determined as follows:
VX = VHe
−
t CT × RT
t = −CT × RT × log e (
VX ) VH
T = −CT × RT × log e (0.1 / 0.8) = 2.1 × CT × RT [s ]
Calculating under the conditions of RT=3.0KΩ and CT=270pF , the oscillating frequency is 588kHz, which is slightly different from the value (600kHz) in the Electrical Characteristics. This difference is caused by characteristics, such as changes in the maximum voltage amplitude of the sawtooth waveform with the CT value and the circuit delay causing the maximum amplitude to become large in the case of a high oscillating frequency even for the same capacitor. It is difficult to incorporate these non-linear characteristics into the equation. In practical use, therefore, the user should read the RT and CT values from the characteristic curve or should determine an approximate target value by using the equation.
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 15 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Switching Regulator Function (1) Reference voltage circuit The reference voltage circuit generates a temperature-compensated reference voltage (~1.25V) from voltage supplied from the power supply pin (pin 3). In addition to providing the reference voltage for the switching regulator, the circuit also sets the idle period. (2) Error amplifier The error amplifier detects the output voltage of the switching regulator and outputs the PWM control signal. The voltage gain is fixed, and connecting a phase compensation capacitor to the FB pin (pin 8) provides stable phase compensation for the system. (3) PWM comparator The voltage comparator has one inverting and three non-inverting inputs. The comparator is a voltage/pulse width converter that controls the ON time of the output pulse depending on the input voltage. The output level is high (H) when the sawtooth wave is lower than the error amplifier output voltage, soft start setting voltage, and idle period setting voltage. (4) Output circuit The output circuit has a totem pole type configuration and can drive an external NPN transistor directly. The value of the ON/OFF current can be set by a resistor connected to the BR/CTL pin (pin 4). Stand-by mode (supply current 1µA or less) can be set by connecting the BR/CTL pin (pin4) to VCC or by making the pin open circuit. (5) Under-Voltage Lockout (UVLO) Transients when powering on or instantaneous glitches in the supply voltage can lead to malfunction of the control IC and cause system damage or failure. The circuit to prevent malfunction at low input voltage detects a low input voltage by comparing the supply voltage to the internal reference voltage. On detection, the circuit fixes the output pin to low. To cancel the status, set VCC below the reset voltage VR (0.9V) and then set VCC up to the recommended operation condition range. By the operation, the latch is canceled to start to operate normally.
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 16 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Small Outline 8-pin Plastic SOP
SYMBOL A B C D E F H J K M L e1 α
INCHES MIN MAX 0.188 0.197 0.149 0.158 0.228 0.244 0.050 BSC 0.013 0.020 0.004 0.010 0.053 0.069 0.011 0.019 0.007 0.010 0.016 0.050 0.150 REF 450 0 80 0
MILLIMETERS MIN MAX 4.80 5.00 3.80 4.00 5.80 6.20 1.27 BSC 0.33 0.51 0.10 0.25 1.35 1.75 0.28 0.48 0.19 0.25 0.40 1.27 3.81 REF 450 0 0 80
NOTES -
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 17 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Small Outline 8-pin TSSOP
SYMBOL A B C D E F H K M α
INCHES MIN MAX 0.114 0.122 0.169 0.177 0.244 0.260 0.026 BSC 0.010 0.012 0.002 0.006 0.041 0.047 0.005 BSC 0.020 0.028 80 00
MILLIMETERS MIN MAX 2.90 3.10 4.30 4.50 6.20 6.60 0.65 BSC 0.25 0.30 0.05 0.15 1.05 1.20 0.127 BSC 0.50 0.70 00 80
NOTES -
* All specs and applications shown above subject to change without prior notice. 1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN Email: server@ceramate.com.tw Tel:886-3-3214525 Http: www.ceramate.com.tw Page 18 of 19 Rev 1.0 Mar.31,2003 Fax:886-3-3521052
CP3800
Switching Regulator Power Controller
Reflow Condition (IR/Convection or VPR Reflow)
Reference JEDEC Standard J-STD-020A
Classification Reflow Profiles Convection or IR/Convction
Average Heating Rate(180°C to peak) Preheat Temperature(125±20°C) Temperature maintained above 180°C Time within 5°C of actual Peak Temperature Peak Temperature Range(Note 1) Cooling Rate Time 25°C to Peak Temperature 5°C/second max. 120 seconds max. 10~150 seconds 10~20 seconds 219~225°C or 235~240°C 6°C /second max. 6 minutes max.
VPR
10°C/second max.
60 seconds 219~225°C or 235~240°C 10°C/second max.
*1 The maximum peak temperatures for IR and VP reflow are depending on package dimensions.
Package Reflow Conditions Pkg. Thickness ≥2.5mm Pkg. Thickness