Philips Semiconductors Product specification SMPS control circuit SG3524 DESCRIPTION PIN CONFIGURATION This monolithic integrated circuit contains all the control circuitry for a regulating power supply inverter or switching regulator. Included in a 16-pin dual-in-line package is the voltage reference, error amplifier, oscillator, pulse-width modulator, pulse steering flip-flop, dual alternating output switches and current-limiting and shut-down circuitry. This device can be used for switching regulators of either polarity, transformer-coupled DC-to-DC converters, transformerless voltage doublers and polarity converters, as well as other power control applications. The SG3524 is designed for commercial applications of 0C to +70C. D, F, N Packages INVERT INPUT 1 16 VREF NON-INV INPUT 2 15 VIN OSC OUTPUT 3 14 EMITTER B (+)CL SENSE 4 13 COLLECTOR B (-)CL SENSE 5 12 COLLECTOR A RT 6 11 EMITTER A CT 7 10 SHUTDOWN GROUND 8 FEATURES * Complete PWM power control circuitry * Single ended or push-pull outputs * Line and load regulation of 0.2% * 1% maximum temperature variation * Total supply current is less than 10mA * Operation beyond 100kHz 9 COMPENSATION TOP VIEW SL00174 Figure 1. Pin Configuration ORDERING INFORMATION TEMPERATURE RANGE ORDER CODE DWG # 16-Pin Plastic Dual In-Line Package (DIP) DESCRIPTION 0 to +70C SG3524N SOT38-4 16-Pin Ceramic Dual In-Line Package (CERDIP) 0 to +70C SG3524F 0582B 16-Pin Small Outline (SO) Package 0 to +70C SG3524D SOT109-1 BLOCK DIAGRAM VREF 16 VIN 15 REF REG +5V TO ALL INTERNAL CIRCUITRY +5V OSCILLATOR 3 OUTPUT FLIP FLOP +5V RT 6 CT 7 (RAMP) 12 OSC 11 13 +5V + 14 E B - INV INPUT 1 +5V ERROR - AMP N.I. INPUT 2 + CB NOR COMPARATOR GROUND 8 (SUBSTRATE) CA NOR +5V + CL - 9 1k 4 +SENSE 5 -SENSE COMPENSATION 10 SHUTDOWN 10k SL00175 Figure 2. Block Diagram 1994 Aug 31 1 853-0891 13721 Philips Semiconductors Product specification SMPS control circuit SG3524 ABSOLUTE MAXIMUM RATINGS SYMBOL PARAMETER RATING UNIT VIN Input voltage 40 V IOUT Output current (each output) 100 mA IREF Reference output current 50 mA Oscillator charging current 5 mA PD Power dissipation Package limitation 1000 mW Derate above 25C 8 mW/C 0 to +70 C -65 to +150 C TA Operating temperature range TSTG Storage temperature range DC ELECTRICAL CHARACTERISTICS TA=0C to +70C, VIN=20V, and f=20kHz, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS LIMITS UNIT Min Typ Max 4.6 5.0 5.4 V Reference section VOUT ISC Output voltage Line regulation VIN=8 to 40V 10 30 mV Load regulation IL=0 to 20mA 20 50 mV Ripple rejection f=120Hz, TA=25C 66 dB Short circuit current limit VREF=0, TA=25C 100 mA Over operating temperature range 0.3 TA=25C 20 mV/kHz kHz Temperature stability Long-term stability 1 % Oscillator section fMAX CT=0.001 F, RT=2k 300 Initial accuracy RT and CT constant 5 Voltage stability VIN=8 to 40V, TA=25C 1 Over operating temperature range 2 Maximum frequency Temperature stability Output amplitude Output pulse width % % % Pin 3, TA=25C 3.5 VP CT=0.01 F, TA=25C 0.5 s Error amplifier section VOS Input offset voltage VCM=2.5V 2 10 mV IBIAS Input bias current VCM=2.5V 2 10 A Open-loop voltage gain 68 VCM Common-mode voltage TA=25C CMRR Common-mode rejection ratio TA=25C BW Small-signal bandwidth VOUT Output voltage 80 1.8 dB 3.4 70 AV=0dB, TA=25C 3 TA=25C 0.5 % each output "ON" 0 V dB MHz 3.8 V 45 % Comparator section Duty cycle IBIAS Input threshold Zero duty cycle 1 Input threshold Maximum duty cycle 3.5 V 1 A Input bias current V Current limiting section Sense voltage Pin 9=2V with error amplifier set for maximum out, TA=25C 180 Sense voltage T.C. VCM 1994 Aug 31 200 220 0.2 Common-mode voltage -1 2 mV mV/C +1 V Philips Semiconductors Product specification SMPS control circuit SG3524 DC ELECTRICAL CHARACTERISTICS (Continued) TA = 0C to +70C, VIN = 20V, and f = 20kHz, unless otherwise specified. SYMBOL PARAMETER LIMITS TEST CONDITIONS Min Typ Max UNIT Output section (each output) Collector-emitter voltage (breakdown) 40 V Collector-leakage current VCE=40V 0.1 50 A Saturation voltage IC=50mA 1 2 V Emitter output voltage VIN=20V 17 18 V tR Rise time RC=2k, TA=25C 0.2 s tF Fall time RC=2k, TA=25C 0.1 s VIN=40V 8 Total standby current (excluding oscillator charging current, error and current limit dividers, and with outputs open) 10 mA connecting Pins 15 and 16 together to the input voltage. In this configuration, the maximum input voltage is 6.0V. THEORY OF OPERATION Voltage Reference This reference regulator may be used as a 5V source for other circuitry. It will provide up to 50mA of current itself and can easily be expanded to higher currents with an external PNP as shown in Figure 3. An internal series regulator provides a nominal 5V output which is used both to generate a reference voltage and is the regulated source for all the internal timing and controlling circuitry. This regulator may be bypassed for operation from a fixed 5V supply by Q1 SG3524 REFERENCE SECTION 100 15 +VIN VREF 16 IL to 1.0A DEPENDING ON CHOICE FOR Q1 + 8 10F GND SL00176 Figure 3. Expanded Reference Current Capability TEST CIRCUIT IS 2k 1W VIN OSC OUT 15 3 VREF 16 SG3524 8 6 7 2 RAMP 1 N.I. INPUT 9 INV. INPUT 10 VIN 8-40V 0.1 RT CT 4 COMP SHUT DOWN 2k 10k 10k 1k 12 13 11 5 14 2k 1W OUTPUTS CURRENT LIMIT 2k SL00177 Figure 4. Test Circuit 1994 Aug 31 3 Philips Semiconductors Product specification SMPS control circuit SG3524 OUTPUT DEAD TIME - microseconds 3.6 V / RT and should be kept within the approximate range of 30A to 2mA; i.e., 1.8k