HT7A6312 Low Power Primary Switcher for Off Line SMPS Features Applications • Fixed 60kHz switching frequency • Off line power supply for battery charger adapters • 9V to 38V wide range VCC voltage • Standby power supply for TV or monitors • Wide AC input range from 85VAC to 265VAC • Auxiliary supply for motor control • PWM with current mode control • Air conditioner power supply • Auxiliary Under Voltage Lock Out with hysteresis • Electromagnetic oven power supply • High voltage start-up current source • Excellent standby low power consumption General Description • Over-temperature, Over-current and Over-voltage protection with auto-restart The HT7A6312 is highly functionally integrated device which combines an integrated PWM controller with current mode control and a high voltage power MOSFET on the same silicon chip. • Integrated 730V MOSFET • Burst mode under low load conditions Typical Power Capability 8SOP 8DIP European (195~265VAC) Type 8W 13W US (85~265VAC) 5W 8W Typical Performance Characteristics Application Circuit Isolation Flyback Topology Snubber Circuit VOUT+ Vac VOUT- SW VCC HT7A6312 VSS PC817 FB TL 431 Rev. 1.00 1 December 24, 2014 HT7A6312 Block Diagram SW VCC Regulator 60kHz Oscillator On/Off Internal Supply OTP Detector UVLO R1 S R2 8V/14.5V R R3 Q Q PWM Latch R4 S 38V Over Voltage Latch FB 0.23V LEB RFB2 RFB1 VSS Pin Assignment VSS 1 8 SW VSS 1 8 SW VSS 2 7 SW VSS 2 7 SW FB 3 6 SW FB 3 6 SW VCC 4 5 SW VCC 4 5 SW HT7A6312 8 DIP-A HT7A6312 8 SOP-A Pin Description Pin No. 8SOP 8DIP 1, 2 1, 2 3 4 3 4 5, 6, 7, 8 5, 6, 7, 8 Rev. 1.00 Pin Name VSS Description Power MOSFET source and circuit ground reference. FB Feedback input. The useful voltage range extends from 0V to 1V, and defines the peak drain MOSFET current. The current limitation, which corresponds to the maximum drain current, is obtained for when the FB pin is shorted to the SOURCE pin. VCC Control circuits power supply. Also provides a charging current during start up thanks to a high voltage current source connected to SW. For this purpose, a hysteresis comparator monitors the VCC voltage and provides two thresholds: VCCON: Voltage value (typically 14.5V) at which the device starts switching and turns off the start up current source. VCCOFF: Voltage value (typically 8V) at which the device stops switching and turns on the start up current source. SW Power MOSFET drain. Also used by the internal high voltage current source during the start up phase to charge the external VCC capacitor. 2 December 24, 2014 HT7A6312 Absolute Maximum Ratings Symbol Parameter VDS(sw) Switching Drain Source Voltage (TJ=25 to 125°C) VDS(st) Start-up Drain Source Voltage (TJ=25 to 125°C)(2) ID Continuous Drain Current VCC Supply Voltage IFB Feedback Current (1) Unit -0.3 to 730 V -0.3 to 400 V Internally limited A 0 to 41 V Electrostatic Discharge: Machine mode VESD Value Electrostatic Discharge: Human body mode 3 mA 400 V 3 kV TC Operating Temperature Range -40 to 150 °C TSTG Storage Temperature Range -55 to 150 °C TJ Junction Operating Temperature Internally limited °C Note: 1.This parameter applies when the start-up current source is off. This is the case when the VCC voltage has reached VCCON and remains above VCCOFF. 2. This parameter applies when the start up current source is on. This is the case when the VCC voltage has not yet reached VCCON or has fallen below VCCOFF. Thermal Data Symbol Parameter 8SOP 8DIP Unit RTHJC Thermal resistance junction-case 25 15 °C/W RTHJA Thermal resistance ambient-case(1) 55 45 °C/W Note: When mounted on a standard single-sided FR4 board with 200mm2 of Cu (at least 35μm thick) connected to all SW pins. Rev. 1.00 3 December 24, 2014 HT7A6312 Electrical Characteristics Symbol Ta=25°C, VCC=18V, unless otherwise specified Parameter Test Conditions Min. Typ. Max. Unit Power Section BVDSS Drain-Source Voltage ID=1mA; VFB=2V 730 — — V IDSS Off State Drain Current VDS=500V; VFB=2V; TJ=125°C — — 0.1 mA rDS(ON) Static Drain-Source On State Resistance ID=0.2A — 19 22 Ω (1) tF Fall Time ID=0.1A; VIN=300V — 100 — nS tR Rise Time ID=0.2A; VIN=300V(1) — 50 — nS COSS Drain Capacitance VDS=25V — 20 — pF Supply Section ICCCH Start-Up Charging Current VDS=100V; VCC=0V to VCCON — -1 — mA ICCOFF Start-Up Charging Current In Thermal Shutdown VCC=5V; VDS=100V TJ > TSD - THYST 0 — — mA Operating Supply Current Not Switching IFB=2mA 0.55 0.65 0.8 mA Operating Supply Current Switching IFB=0.5mA; ID=50mA(2) 0.5 0.7 0.9 mA % ICC DRST Restart Duty-Cycle — — 16 — VCCOFF VCC Under-voltage Shutdown Threshold — 7 8 9 V VCCON VCC Start-Up Threshold — 13 14.5 16 V VCCHYST VCC Threshold Hysteresis — 5.8 6.5 7.2 V VCCOVP VCC Over-voltage Threshold — 35 38 41 V VCC=VCCOFF to 35V; TJ=0 to 100°C 54 60 66 kHz — Oscillation Section Oscillator Frequency Total Variation fOSC PWM Comparator Section GID IFB to ID Current Gain IDLIM Peak Current Limitation — IFBSD IFB Shutdown Current RFB FB Pin Input Impedance ID=0mA ID=0.2A VFB=0V — — 320 — 0.32 0.4 0.48 A — 0.9 — mA — 1.2 — kΩ nS tD Current Sense Delay to Turn-Off — 200 — tB Blanking Time — — 350 — nS tONMIN Minimum Turn-On Time — — 550 — nS Over-temperature Section TSD Thermal Shutdown Temperature — 140 170 — °C THYST Thermal Shutdown Hysteresis — — 40 — °C Note: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. The guaranteed specifications apply only for the test conditions listed. 1. For clamped inductive load 2. These test conditions are obtained with a resistive load which permit the maximum conduction time of the device. Rev. 1.00 4 December 24, 2014 HT7A6312 Functional Description Under Voltage Lock Out – UVLO The HT7A6312 is highly functionally integrated device which combines an integrated PWM controller with current mode control and a high voltage power MOSFET on the same silicon chip. The secondary side feedback signal passes through a photo-coupler on the primary side while the output voltage is regulated by the device according to the feedback signal. The device has a small quiescent current and low power consumption when operating in the standby mode. It also has a range of protection features to protect the controller from fault conditions. When the fault condition happens, the device will shut down the power MOSFET and cause the VCC voltage to fall. When the VCC voltage is lower than the UVLO lower voltage (8V), the protection circuits will be reset and the internal high voltage start up current source will charge the VCC capacitor. Not until the VCC voltage reaches the UVLO higher voltage (14.5V), the device will resume normal operation. In this way, the auto-restart function can enable and disable the power MOSFET switching alternately until the fault condition is eliminated. High Voltage Start up Thermal Shutdown – TSD The SW pin in the device is a high voltage start up current source. This current source will generate a current which is regulated from a high voltage and which will charge the VCC pin until the UVLO is triggered when an AC voltage is applied on the converter input. When the VCC voltage is larger than the UVLO trigger voltage, the high voltage start up current source will be cut off by UVLO and the device will start operation by switching the power MOSFET on and off. Because the device integrates the controller and the power MOSFET on the same chip, the temperature of the device including the power MOSFET can be easily detected. When the temperature is over 170°C, the thermal shutdown protection function will be active to turn off the power MOSFET. The device will resume normal operation when the device temperature is lower than the recovery temperature of about 130°C and when the VCC voltage is lower than 2V. Over Voltage Protection – OVP Feedback When a malfunction occurs in the secondary side feedback circuit, or if a wiring defect allows the feedback loop to be open, the current through the opto-coupler will be near to zero. At this time, as the excess energy will be supplied to the output, the output voltage may be higher than the regulated voltage and may damage the components in the secondary side. The device includes an over voltage protection function to avoid this condition happening. If the V CC voltage is higher than 38V, the device will be shut down by the OVP protection function to prevent the malfunctions from damaging components. The FB pin determines the device operation. The power MOSFET current will be sensed by the current sensing resistor which is connected between the source terminal of the power MOSFET and the ground terminal. In addition, this sensing resistor also senses the current coming from the FB pin. The voltage across the resistor will be compared to a fixed reference voltage (0.23V). The power MOSFET is turned off when the sensing resistor voltage is larger than 0.23V. Leading Edge Blanking – LEB When the power MOSFET is turned on, there is usually a high current spike which is generated by the primary side capacitor and the secondary side rectifier diode reverse recovery. This spike will be sensed by the sensing resistor to indicate an excessive voltage which will in turn lead to false feedback operation in the current mode PWM control circuit. In order to avoid this problem, the device includes a leading edge blanking circuit which inhibits the comparator for a short time after the power MOSFET is turned on. Rev. 1.00 5 December 24, 2014 HT7A6312 Application Circuits Buck Topology EMI Solution VCC FB HT7A6312 VSS SW VOUT+ Vac VOUT- Buck − Boost Topology EMI Solution VCC FB HT7A6312 SW VSS VOUT- Vac VOUT+ Non-Isolation Flyback Topology Snubber Circuit VOUT1 Vac VOUT2 VCC SW HT7A6312 FB VSS Rev. 1.00 6 December 24, 2014 HT7A6312 Package Information Note that the package information provided here is for consultation purposes only. As this information may be updated at regular intervals users are reminded to consult the Holtek website for the latest version of the package information. Additional supplementary information with regard to packaging is listed below. Click on the relevant section to be transferred to the relevant website page. • Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications) • Packing Meterials Information • Carton information Rev. 1.00 7 December 24, 2014 HT7A6312 8-pin DIP (300mil) Outline Dimensions Symbol Min. Nom. Max. A 0.355 0.365 0.400 B 0.240 0.250 0.280 C 0.115 0.130 0.195 D 0.115 0.130 0.150 E 0.014 0.018 0.022 F 0.045 0.060 0.070 G — 0.100 BSC — H 0.300 0.310 0.325 I — — 0.430 Symbol Rev. 1.00 Dimensions in inch Dimensions in mm Min. Nom. Max. 10.16 A 9.02 9.27 B 6.10 6.35 7.11 C 2.92 3.30 4.95 D 2.92 3.30 3.81 E 0.36 0.46 0.56 F 1.14 1.52 1.78 G — 2.54 BSC — H 7.26 7.87 8.26 I — — 10.92 8 December 24, 2014 HT7A6312 8-pin SOP (150mil) Outline Dimensions Symbol Dimensions in inch Min. Nom. A — 0.236 BSC — B — 0.154 BSC — Max. 0.020 C 0.012 — C′ — 0.193 BSC — D — — 0.069 E — 0.050 BSC — F 0.004 — 0.010 G 0.016 — 0.050 H 0.004 — 0.010 α 0° — 8° Symbol Rev. 1.00 Dimensions in mm Min. Nom. Max. A — 6.00 BSC — B — 3.90 BSC — C 0.31 — 0.51 C′ — 4.90 BSC — D — — 1.75 E — 1.27 BSC — F 0.10 — 0.25 G 0.40 — 1.27 H 0.10 — 0.25 α 0° — 8° 9 December 24, 2014 HT7A6312 Copyright© 2014 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek's products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw. Rev. 1.00 10 December 24, 2014