IP1524 SERIES SEME LAB TOP VIEW INV. INPUT 1 16 VREF N. I. INPUT 2 15 VIN OSC. OUTPUT 3 14 EB +C.L. SENSE 4 13 CB –C.L. SENSE 5 12 CA RT 6 11 EA FEATURES CT 7 10 SHUTDOWN GROUND 8 9 • • • • • REGULATING PULSE WIDTH MODULATORS COMPENSATION J Package – 16 Pin Ceramic DIP N Package – 16 Pin Plastic DIP D Package – 16 Pin Plastic (150) SOIC Guaranteed ±2% reference voltage tolerance Guaranteed ±6% oscillator tolerance Fully specified temperature performance Guaranteed 10mV/1000 hours long term stability Interchangeable with SG1524 series Order Information Part Number IP1524 IP2524 IP3524 J–Pack 16 Pin ✔ ✔ ✔ N–Pack 16 Pin D–16 16 Pin ✔ ✔ ✔ ✔ Temp. Range -55 to +125°C -25 to +85°C 0 to +70°C Note: To order, add the package identifier to the part number. eg. IP1524J IP3524D–16 ABSOLUTE MAXIMUM RATINGS (Tcase = 25°C unless otherwise stated) +VIN Input Voltage +40V Collector Voltage +40V Output Current (each transistor) Reference Load Current 100mA Internally Limited Oscillator Charging Current 5mA Shut Down Pin Voltage +5.5V Current Limit Sense Common Mode Range –1.0 to +1.0V PD Power Dissipation TA = 25°C Derate @ TA > 50°C 1W 10mW/°C PD Power Dissipation TC = 25°C Derate @ TC > 25°C 2W 16mW/°C TJ Operating Junction Temperature TSTG Storage Temperature Range TL Lead Temperature Semelab plc. See Ordering Information –65 to +150°C (soldering, 10 seconds) Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. +300°C Prelim. 3/95 IP1524 SERIES SEME LAB DESCRIPTION The IP1524 series of PWM switching regulator control circuits contains all the functions required to implement singleended or push-pull switching regulators. Included are voltage reference, error amplifer, oscillator, PWM comparator, output drivers, current limiting and shutdown circuitry. Although functionally indentical to the SG1524 series, SEMELAB has incorporated several improvements to the IP1524 allowing tighter and more complete specification of electrical performance. BLOCK DIAGRAM 16 VIN RT CT 15 REFERENCE REGULATOR +5V TO ALL INTERNAL CIRCUITRY OSCILLATOR OUTPUT 6 7 12 3 CA NOR FLIP FLOP OSCILLATOR 11 13 EA CB +5V COMPARATOR NOR INV. INPUT N.I. INPUT GND (SUBSTRATE) SHUTDOWN 1 ERROR AMP 4 +5V C.L. 2 +5V EB +SENSE –SENSE COMPENSATION 8 10 9 5 14 1kΩ 10kΩ RECOMMENDED OPERATING CONDITIONS VIN Input Voltage +8 to +40V Collector Voltage 0 to +40V Error Amp Common Mode Range Output Current +1.8 to +3.4V (each transistor) Reference Load Current 0 to 100mA 0 to 20mA Oscillator Charging Current 30µA to 2mA Oscillator Frequency Range 50Hz to 500kHz RT Oscillator Timing Resistor CT Oscillator Timing Capacitor TAMB Operating Ambient Temperature Range Semelab plc. 1.8kΩ to 100kΩ 1nF to 0.1µF IP1524 IP2524 IP3524 Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. –55 to +125°C -25 to +85°C 0 to +70°C Prelim. 3/95 IP1524 SERIES SEME LAB ELECTRICAL CHARACTERISTICS (TJ = 25°C unless otherwise stated) Parameter Test Conditions 1 IP1524 IP2524 Min. Typ. Max. Min. 4.90 4.60 IP3524 Typ. Max. Units REFERENCE SECTION Output Voltage TJ = Over Temp. Range Line Regulation +VIN = 8 to 40V Load Regulation IL = 0 to 20mA Ripple Rejection f = 120Hz Short Circuit Current VREF = 0 Temperature Stability TJ = Over Temp. Range Long Term Stability TJ = 125°C 5.00 5.40 10 10 30 20 20 50 5.00 5.10 TJ = Over Temp. Range 1 TJ = Over Temp. Range 5 80 TJ = Over Temp. Range 25 V mV 66 dB mA 50 120 100 0.3 1 0.3 1 10 20 6 5 0.1 1 0.5 1 2 120 240 1 % mV khr OSCILLATOR SECTION Initial Accuracy RT = 2.7kΩ Voltage Stability +VIN = 8 to 40V Temperature Stability TJ = Over Temp. Range Minimum Frequency Maximum Frequency RT = 100kΩ CT = 0.1µF RT = 2kΩ CT = 0.001µF TJ = Over Temp. Range CT = 0.01µF Sawtooth Valley Voltage CT = 0.01µF Output, Pin 3 CT = 0.01µF TJ = Over Temp. Range Clock Pulse Width Output, Pin 3 CT = 0.01µF ERROR AMP SECTION 1 2 Hz 300 300 kHz 3.6 3.6 0.6 1 1 3.0 4.0 3.5 V 0.3 0.5 1.0 0.5 µs 200 V 2 Input Offset Voltage TJ = Over Temp. Range 0.1 5 2 10 Input Bias Current TJ = Over Temp. Range 1 2 1 10 Input Offset Current TJ = Over Temp. Range DC Open Loop Gain TJ = Over Temp. Range Output Low Level VPIN1 – VPIN2 ≥ 150mV Output High Level VPIN2 – VPIN2 ≥ 150mV 1 0.5 72 60 80 80 3.8 3.8 +VIN = 8 to 40V 70 90 70 70 100 70 Gain Bandwidth Product 3 mV µA dB 0.5 0.5 Common Mode Rejection Supply Voltage Rejection % 120 TJ = Over Temp. Range Sawtooth Peak Voltage Clock Amplitude CT = 0.01µF V dB 3 MHz NOTES 1. Test Conditions unless otherwise stated: VIN = 20V , IREF = 0. 2. VCM = +1.8 to +3.4V 3. VCM = -1 to +1V Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 3/95 IP1524 SERIES SEME LAB ELECTRICAL CHARACTERISTICS (TJ = 25°C unless otherwise stated) Parameter IP1524 IP2524 Min. Typ. Max. Test Conditions 1 Min. IP3524 Typ. Max. Units PWM COMPARATOR Minimum Duty Cycle Maximum Duty Cycle VPIN1 – VPIN2 ≥ 150mV 0 0 TJ = Over Temp. Range VPIN2 – VPIN1 ≥ 150mV TJ = Over Temp. Range 45 49 190 200 210 170 200 230 45 49 180 200 % % CURRENT LIMIT AMPLIFIER 3 VCM = 0 Sense Voltage VCM = 0 TJ = Over Temp. Range 220 200 mV SHUTDOWN INPUT VPIN9 ≤ 0.6V High Input Voltage TJ = Over Temp. Range VSHUTDOWN = +5V High Input Current 4 TJ = Over Temp. Range VPIN9 ≥ 3.5V Low Input Voltage 1.2 1.2 TJ = Over Temp. Range V 4 8 mA 0.3 0.3 V OUTPUT SECTION (each transistor) Collector – Emitter Voltage IC = 50µA TJ = Over Temp. Range Collector Leakage Current VCE = 40V TJ = Over Temp. Range 0.1 50 0.1 50 µA IC = 50mA TJ = Over Temp. Range 1 2 1 2 V Emitter Output Voltage VIN = 20V TJ = Over Temp. Range Emitter Voltage Rise Time RE = 2kΩ 0.2 0.4 0.2 Collector Voltage Fall Time RC = 2kΩ 0.1 0.2 0.1 5 10 5 Collector Saturation Voltage 40 40 17 18 17 V 18 V µs POWER CONSUMPTION Standby Current VIN = 40V TJ = Over Temp. Range 10 mA NOTES 1. Test Conditions unless otherwise stated: VIN = 20V , IREF = 0. 2. VCM = +1.8 to +3.4V 3. VCM = -1 to +1V Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 3/95 IP1524 SERIES SEME LAB APPLICATIONS INFORMATION The IP1524 is a fixed-frequency pulse-width modulation voltage regulator control circuit. The regulator operates at a frequency that is programmed by one timing resistor (RT) and one timing capacitor (CT). RT establishes a constant charging current for CT, which is fed to the comparator providing linear control of the output pulse width by the error amplifier. The IP1524 contains an on-board 5V regulator that serves as a reference as well as powering the IP1524’s internal control circuitry and is also useful in supplying external support functions. This reference voltage is lowered externally by a resistor divider to provide a reference within the common-mode range of the error amplifier or an external reference may be used. The power supply output is sensed by a second resistor divider network to generate a feedback signal to the error amplifier. The amplifier output voltage is then compared to the linear voltage ramp at C T . The resulting modulated pulse out of the high-gain comparator is then steered to the appropriate output pass transistor (Q1 or Q2) by the pulse-steering flip-flop, which is synchronously toggled by the oscillator output. 0.9 mH + 28 V 68Ω 5kΩ 5k Ω 0. 1µF N. I. CA + 28 V 5kΩ 150 Ω VRE F EB CT CL + OS C. C L- 0.1µF 2kΩ 0. 02µF SH .DOWN GND CA N. I. EA VRE F CB RT EB CT CL + OS C. C L- 1kΩ 5kΩ 1kΩ 20 T 5 T 20 T 5 T 1 0 0µF 5V 5A 0 . 1Ω 1 0 0µ F COM P. 0.0 01µF SH .DOWN GND COMP . 0.001µF 20k Ω GND RE TURN 0 . 1Ω In this conventional single-ended regulator circuit, the two outputs of the IP1524 are connected in parallel for effective 0-90% duty cycle modulation. The use of an output inductor requires an R-C phase compensation network for loop stability. Semelab plc. 1kΩ 1W 0. 01µF 50k Ω RE TURN 1kΩ 1W VI N INV. 1mH 5kΩ 5 0 0µF 2kΩ CB RT 5k Ω 1 N3 8 80 EA 5kΩ 3kΩ +5V 1A VI N I NV . 5kΩ The oscillator output pulse also serves as a blanking pulse to assure both outputs are never on simultaneously during the transition times. The width of the blanking pulse is controlled by the value of CT. The outputs may be applied in a push-pull configuration in which their frequency is half that of the base oscillator, or paralleled for single-ended applications in which the frequency is equal to that of the oscillator. The output of the error amplifier shares a common input to the comparator with the current limiting and shutdown circuitry and can be overridden by signals from either of these inputs. This common point is also available externally and may be employed to control the gain of, or to compensate, the error amplifier, or to provide additional control to the regulator. Push-pull outputs are used in this transformer-coupled DC-DC regulating converter. Note that the oscillator must be set at twice the desired output frequency as the IP1524’s internal flip-flop divides the frequency by 2 as it switches the PWM signal from one output to the other. Current limiting is done in the primary so that the pulse width will be reduced should transformer saturation occur. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 3/95 IP1524 SERIES SEME LAB TYPICAL PERFORMANCE CHARACTERISTICS Open-Loop Voltage Amplification of Error Amplifier vs. Frequency 80 70 1M VIN = 20V RL = ∞ TJ = 25˚C RL = 1MΩ 60 RL = 300kΩ 50 RL = 100kΩ OSCILLATOR FREQUENCY (Hz) OPEN LOOP VOLTAGE AMPLIFICATIO N (dB) 90 R = 30kΩ 40 L 30 20 10 Oscillator Frequency vs. Timing Components Note: Value of RL below 30k Ω will begin to limit the maximum duty cycle. C T 100k C C T C 1k . 00 =0 .0 =0 .01 T =0 .0 T =0 .1 1 µF 03 T 10k C =0 µF µF 3µ F µF VIN = 20V TJ = 25˚C 0 -10 100 100 1k 10k 100k 1M 1 10M 2 5 RT FREQUENCY (Hz) Output Dead Time vs. Timing Capacitance Value 10 10 20 TIMING RESISTOR (kΩ) 4 VIN = 20V COLLECTOR – EMITTER VOLTAGE (V) TJ = 25˚C OUTPUT DEAD TIME (µs) 100 Output Saturation Voltage vs. Load Current VIN = 20V 1 Note: Dead Time = Oscillator output pulse width plus output delay. 0.1 3 TJ 2 2 =1 TJ = 5˚ C 2 5˚ TJ = C - 5 5˚ C 1 0 0.001 0.01 C Semelab plc. 50 T 0.1 0 TIMING CAPACITOR (µF) Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. 20 40 60 80 100 LOAD CURRENT (mA) Prelim. 3/95