Document
Philips Semiconductors
Product specification
SMPS control circuit
SG3524
DESCRIPTION
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 0°C to +70°C.
PIN CONFIGURATION
D, F, N Packages
INVERT INPUT 1 NON-INV INPUT 2 OSC OUTPUT 3 (+)CL SENSE 4 (–)CL SENSE 5 RT CT 6 7 16 VREF 15 VIN 14 EMITTER B 13 COLLECTOR B 12 COLLECTOR A 11 EMITTER A 10 SHUTDOWN 9 TOP VIEW COMPENSATION
FEATURES
GROUND 8
• 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
ORDERING INFORMATION
DESCRIPTION 16-Pin Plastic Dual In-Line Package (DIP) 16-Pin Ceramic Dual In-Line Package (CERDIP) 16-Pin Small Outline (SO) Package
SL00174
Figure 1. Pin Configuration
TEMPERATURE RANGE 0 to +70°C 0 to +70°C 0 to +70°C
ORDER CODE SG3524N SG3524F SG3524D
DWG # SOT38-4 0582B SOT109-1
BLOCK DIAGRAM
VREF 16 VIN 15 REF REG +5V TO ALL INTERNAL CIRCUITRY +5V OSCILLATOR 3 OUTPUT FLIP FLOP
12 NOR 11
CA
+5V RT 6 CT 7 (RAMP) OSC
+5V + COMPARATOR – +5V ERROR – AMP + 1k 10 SHUTDOWN 10k 9 COMPENSATION +5V + CL – 4 +SENSE NOR
13
CB
14 E B
INV INPUT 1 N.I. INPUT 2 GROUND 8 (SUBSTRATE)
5 –SENSE
SL00175
Figure 2. Block Diagram
1994 Aug 31
1
853-0891 13721
Philips Semiconductors
Product specification
SMPS control circuit
SG3524
ABSOLUTE MAXIMUM RATINGS
SYMBOL VIN IOUT IREF PD Input voltage Output current (each output) Reference output current Oscillator charging current Power dissipation Package limitation Derate above 25°C TA TSTG Operating temperature range Storage temperature range 1000 8 0 to +70 -65 to +150 mW mW/°C °C °C PARAMETER RATING 40 100 50 5 UNIT V mA mA mA
DC ELECTRICAL CHARACTERISTICS
TA=0°C to +70°C, VIN=20V, and f=20kHz, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS LIMITS Min 4.6 VIN=8 to 40V IL=0 to 20mA f=120Hz, TA=25°C VREF=0, TA=25°C Over operating temperature range TA=25°C CT=0.001 µF, RT=2kΩ RT and CT constant VIN=8 to 40V, TA=25°C Over operating temperature range Pin 3, TA=25°C CT=0.01 µF, TA=25°C VCM=2.5V VCM=2.5V 68 TA=25°C TA=25°C AV=0dB, TA=25°C TA=25°C % each output “ON” Zero duty cycle Maximum duty cycle 0.5 0 1 3.5 1 Pin 9=2V with error amplifier set for maximum out, TA=25°C 180 200 0.2 -1 +1 220 1.8 70 3 3.8 45 3.5 0.5 2 2 80 3.4 10 10 Typ 5.0 10 20 66 100 0.3 20 300 5 1 2 1 Max 5.4 30 50 UNIT
Reference section
VOUT Output voltage Line regulation Load regulation Ripple rejection ISC Short circuit current limit Temperature stability Long-term stability V mV mV dB mA % mV/kHz kHz % % % VP µs mV µA dB V dB MHz V % V V µA mV mV/°C V
Oscillator section
fMAX Maximum frequency Initial accuracy Voltage stability Temperature stability Output amplitude Output pulse width
Error amplifier section
VOS IBIAS VCM CMRR BW VOUT Input offset voltage Input bias current Open-loop voltage gain Common-mode voltage Common-mode rejection ratio Small-signal bandwidth Output voltage Duty cycle Input threshold Input threshold IBIAS Input bias current Sense voltage Sense voltage T.C. VCM Common-mode voltage
Comparator section
Current limiting section
1994 Aug 31
2
Philips Semiconductors
Product specification
SMPS control circuit
SG3524
DC ELECTRICAL CHARACTERISTICS (Continued)
TA = 0°C to +70°C, VIN = 20V, and f = 20kHz, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS LIMITS Min 40 VCE=40V IC=50mA VIN=20V RC=2kΩ, TA=25°C RC=2kΩ, TA=25°C 17 0.1 1 18 0.2 0.1 50 2 Typ Max UNIT
Output section (each output)
Collector-emitter voltage (breakdown) Collector-leakage current Saturation voltage Emitter output voltage tR tF Rise time Fall time (excluding oscillator charging current, error and current limit dividers, and with outputs open) V µA V V µs µs
Total standby current
VIN=40V 8 10 mA
THEORY OF OPERATION Voltage Reference
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
connecting Pins 15 and 16 together to the input voltage. In this configuration, the maximum input voltage is 6.0V. 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 PN.