HT7A6002 High Performance Current Mode PWM Controller Feature General Description • High performance, low cost current mode PWM controller especially designed for energy star 5.0 The HT7A6002 is a high performance, low cost Current Mode PWM controller for providing necessary feature to implement Off-Line application. By Optimizing for the Energy Star 5.0 spec., the Power Supply Unit (PSU) implemented using the HT7A6002 can satisfy the “Energy Star No-Load Mode” Stand-by Power standard, which is less than 0.3W within all Nameplate Output Power Range of 0~250W. Internally implemented circuits include a trimmed Oscillator for precise frequency control, a temperature-compensated Voltage Reference, Slope Compensation, Leading-Edge Blanking, and a patented Non-Audible Noise Green Mode Control Scheme. • High-Voltage CMOS process with excellent ESD protection (>3KV) • Very low startup current (<20μA) and operating current • ±5% trimmed oscillator for precise frequency control • Non-audible-noise Green Mode control • LEB (Leading-Edge Blanking) on CS pin • Internal slope compensation • Programmable switching frequency • Internally trimmed reference with UVLO (Under Voltage Lockout) The HT7A6002 features a range of various protection functions such Short-Circuit Protection (SCP, which can also be used for Over-Load Protection, OLP), Cycle-by-Cycle Current Limiting and Under Voltage Lock-Out (UVLO). • Cycle-by-Cycle Current Limiting • Build-in Short-Circuit-Protection(SCP) for Short-Circuit and Over-Load condition • 8-Pin SOP package Applications • Switching AC-DC adaptor • Open frames switching power supply • LCD TV Application Circuits EMI Filter Flyback Converter VOUT RT GD HT7A6002 GND CS VCC COMP VREF 0.1uF Rev. 1.20 Voltage Sense GND 1 FOD817 TL431 March 23, 2016 HT7A6002 Block Diagram Pin Assignment VREF VCC UVLO Driver Stage RT S GD Q GND R Slop Compensation PWM 2R COMP 14V / 8V Green Mode OSC VCC Internal Bias & Vref 32V R OCP CS LEB 350nS SCP 1V Pin Description Pin No. Pin Name Description 1 COMP 2 N.C No connection 3 CS A voltage proportional to inductor current is connected to this input. The PWM generator uses this voltage information to terminate the output switch conduction. 4 RT The oscillator frequency is programmed by connecting a resistor RT between this pin and ground. A maximum frequency of 500KHz is possible. 5 GND 6 GD 7 VCC Positive Supply. 8 VREF Reference output. Voltage Feedback Pin. Connected to a Photo-Coupler for close-loop control. Combined control circuitry and power ground. Power MOSFET gate driver output. Absolute Maximum Ratings Supply Voltage VCC�������������������������������������������������������������������������������������������������������������������������������� -0.3V~30.0V COMP, RT, CS Pins����������������������������������������������������������������������������������������������������������������������������������� -0.3V~5.5V Junction Temperature������������������������������������������������������������������������������������������������������������������������������������������ 150°C Operating Ambient Temperature��������������������������������������������������������������������������������������������������������������� -40°C~85°C Storage Temperature Range�������������������������������������������������������������������������������������������������������������������� -65°C~150°C Package Thermal Resistance (8-Pin SOP)����������������������������������������������������������������������������������������������������� 160°C/W ESD Protection: Human Body Model���������������������������������������������������������������������������������������������������������������������������������������3kV Machine Model��������������������������������������������������������������������������������������������������������������������������������������������200V Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings” may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Rev. 1.20 2 March 23, 2016 HT7A6002 Electrical Characteristics Unless otherwise stated, this specifications apply for 0°C ≤ Ta ≤ 70°C, VCC=15V, RT=10kW Symbol Parameter Test Condition Min. Typ. Max. Unit Supply Voltage (VCC Pin) Startup Current IST VCC=12.9V — 12 30 mA VCOMP=0V — 2.0 3.0 mA VCOMP=3V — 2.5 — mA ICC Operating Current VTL UVLO (Off) — 7 8 9 V VTH UVLO (On) — 13 14 15 V Reference Section VREF Output Voltage Tj = 25°C, IO = 1mA — 5.5 — V ∆VREF Line Regulation 12V ≤ VCC ≤ 25V — 3 20 mV ∆VREF Load Regulation 1mA ≤ IO ≤ 10mA — 4 25 mV Current Sensing (CS Pin) VCS(OFF) Maximum Input Voltage, Vcs(off) — 0.9 1.0 1.1 V tLEB Leading Edge Blanking Time — — 350 — ns Delay to Output — — 100 — ns Oscillator Frequency Tj=25°C, RT=10kW (See Note *) 49 52 55 kHz ∆fOSC ∆TA Temp. Stability -40°C ~105°C — 5 — % ∆fOSC ∆VREF Voltage Stability VCC=10V~25V — 0.2 1.0 %/V DMAX Maximum Duty — 75 — % Oscillator (RT pin) fOSC — Gate Drive Output (GD Pin) VOL Output Low Level VCC=15V, Isink=20mA — — 1 V VOH Output High Level VCC=15V, Isource=20mA 9 — — V tr Rising Time Tj=25°C, Load Capacitance=1nF — 50 150 ns tf Falling Time Tj=25°C, Load Capacitance=1nF — 50 150 ns Voltage Feedback (COMP Pin) ISINK Short Circuit Current VCOMP=0V — 1.5 2.2 mA VCOMP Open Loop Voltage COMP pin open — 5.5 — V SCP Trip Level VCOMP (SCP) — 4.7 — V SCP Delay Time (See Note) fS=52kHz — 40 — ms SCP (Short Circuit Protection) VCOMP Note: These Parameters, although guaranteed, are not 100% tested in production. "*" It is necessary that the operating frequency is set at 40kHz~60kHz for Green Mode operation. The relationship between the resistor value of external RT and the operating frequency is provided in the Figure 13. (page 7). Rev. 1.20 3 March 23, 2016 HT7A6002 Typical Performance Characteristics 15.5 10 9.5 UVLO (off)(V) UVLO (on)(V) 15 14.5 14 13.5 13 12.5 8 7.5 7 12 11.5 9 8.5 6.5 -40 -20 0 20 40 60 80 100 6 120 -40 10 Temperature (degree C) Frequency (KHz) Frequency (KHz) -20 0 20 40 60 80 100 120 57 56 55 54 53 52 51 50 49 48 47 11 13 15 17 Temperature (degree C) 0 20 40 60 80 100 Vcomp (V) 23 25 31 29 27 25 23 21 19 17 15 11 120 Temperature (degree C) 13 15 17 19 21 23 25 Vcc (V) Figure 6. Green Mode Frequency vs Vcc Figure 5. Vcomp for SCP vs Temperature Rev. 1.20 21 Figure 4. Frequency vs Vcc Green Mode Frequency (KHz) -20 19 Vcc (V) Figure 3. Frequency vs Temperature 4.9 4.85 4.8 4.75 4.7 4.65 4.6 4.55 4.5 4.45 4.4 -40 110 Figure 2. UVLO (off)(V) vs Temperature Figure 1. UVLO (on) (V) vs Temperature 57 56 55 54 53 52 51 50 49 48 47 -40 60 Temperature (degree C) 4 March 23, 2016 HT7A6002 Application Information Base on device field test demo board results, for the Full-Range (115V, 230V Vac) input, the Stand-by Power will remain less than 0.3W@Pno=60W(as shown in Table 2).This is within the Energy Star 5.0 criteria. Operation Overview The HT7A6002 is an excellent, low power off-line PWM Controller. With a high degree of functional integration, the external component requirement is greatly reduced resulting in excellent performance/ cost ratios. The device integrates many enhanced features such as a Non-Acoustic-Noise Green Mode Oscillator, Internal Slope Compensation, Internal Leading-Edge Blanking, Short-Circuit Protection and a wide industrial operating temperature range (-40°C to 85°C). The device is designed for primary side control / secondary side feedback applications and is optimized for the Energy Star 5.0 specification, this ensures that any EPS (External Power Supply) implemented using the HT7A6002 can fully satisfy the Energy Star 1.1/2.0 Stand-by (No-Load) criteria. Demo Board Input Condition (Pno=60 watts) 0 to < 50 watts ≥ 50 to ≤ 250 watts Stand-by Power 115V VAC < 0.3W 230V VAC < 0.3W Table 2. Demo Board Stand-by Power Results Advanced Precise-Oscillator for GreenMode Switching and Non-Acoustic Noise Requirement A Trimmed Precise Green Mode Oscillator is implemented in the device to enhance the conversion efficiency under conditions of light loads. As the data shown in Fig. 8, the efficiency difference of the traditional current mode PWM Controller between light loads and heavy loads is more than 8%, while the average efficiency is only 82%, the efficiency difference of the HT7A6002 is only 1%, while average efficiency is up to 87.5%. Energy Consumption Criteria for No-Load Nameplate Output Power (Pno) Input Range Maximum Power in No-Load AC-AC EPS AC-DC EPS ≤ 0.5 watts ≤ 0.3 watts ≤ 0.5 watts ≤ 0.3 watts Table 1. Energy Star 5.0 No-Load Criteria Ultra Low Stand-by Power for Energy Star 5.0 and Later Energy Star Requirement The device contains many advanced control schemes for Low Stand-by Power like tiny Operating/Standby Current, Green Mode for Light-Load, etc. By choosing an appropriate Stand-by resistor (as shown in Figure 7), EPS implemented by the device can fully satisfy the Energy Star 5.0 No-Load criteria. HT7A6002 Figure 7. Stand-by Resistor Figure 8. Efficiency Comparison between HT7A6002 & Traditional Current Mode PWM Controller (Measured at HT7A6002 Demo Board) Rev. 1.20 5 March 23, 2016 HT7A6002 The Green Mode Oscillator types supplied by other PWM Controller providers are plagued by the problems of Acoustic-Noise. This is because, under the conditions of light loads, the frequency will keep decreasing through Human Acoustic Range (from 20Hz to 20kHz), these audio frequencies may create audible noise in the transformer. Holtek’s HT7A6002 patented Green Mode Oscillator designed using an advanced Non-Acoustic Noise Scheme to prevent the generation of frequencies in the audio frequency band, thus eliminating any transformer noise. Start-up Current (~uA) Figure 10. UVLO Scheme and Start-Up Current Current Sense and Leading-Edge Blanking (LEB) A Leading-Edge Blanking Scheme is integrated in the device to prevent false triggering due to feedback current spikes which may appear on the CS pin, further eliminate the need for R-C filter which is always a requirement in the traditional current mode PWM Controller applications. HT7A6002 Figure 9. Oscillator Behavior Compared with HT7A6002 HT7A6002 and other Green Mode PWM Controller Under Voltage Lockout (UVLO) An UVLO comparator is implemented in to ensure that the device is fully functional before the output stage is enabled. As shown in Fig. 10, a hysteresis is provided to prevent the PWM Controller from shutting down during any voltage dips which might occur during startup process. The turn-on and turnoff threshold levels are set at 14.0V and 8.0V, respectively. Rev. 1.20 Figure 11. LEB with R-C Filter Removed 6 March 23, 2016 HT7A6002 Internal Slope-Compensation Oscillator Frequency Tuning An important issue with the current mode control schemes is the instability due to Sub-Harmonic Oscillation when the Duty-Cycle > 50%. To prevent this problem from occurring, a Slope-Compensation function is always necessary. In traditional current mode PWM Controller application, many external components are necessary for Slope-Compensation function, but in HT7A6002 the internal SlopeCompensation eliminates the need for these external components resulting in simplified the application circuit design. By choosing an appropriate value of an external resistor between the RT Pin and GND, a suitable operating frequency can be generated. The relationship between the value of RT and the operating frequency is provided in the Figure 13. Short-Circuit Protection (SCP) and Over-Load Protection (OLP) To protect all the devices of a system from being damaged under over load or short circuit conditions, a smart SCP function is implemented in the device. Here the feedback system will force the voltage loop to move toward a saturation value and then pull up the voltage on the COMP pin. Whenever the VCOMP increases to the SCP threshold of 4.7V and remains there for longer than 40ms, the protection scheme will activate and then turn off the gate output to stop the switching of power circuit. By using such a protection mechanism, the average input power can be reduced to a very low level so that the component temperature and stress can be controlled within safe operating levels. Figure 13. RT Resistor Value vs Operating Frequency VCC SCP UVLO(off) SCP Reset 40ms 4.7V SCP trip Level Figure 12. SCP Function Behavior Rev. 1.20 7 March 23, 2016 HT7A6002 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. 1.20 8 March 23, 2016 HT7A6002 8-pin SOP (150mil) Outline Dimensions Symbol Dimensions in inch Min. Nom. Max. A — 0.236 BSC — B — 0.154 BSC — C 0.012 — 0.020 C′ — 0.193 BSC — 0.069 D — — E — 0.050 BSC — F 0.004 — 0.010 G 0.016 — 0.050 H 0.004 — 0.010 α 0° — 8° Symbol Rev. 1.20 Dimensions in mm Min. Nom. Max. — A —F 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 March 23, 2016 HT7A6002 Copyright© 2016 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. 1.20 10 March 23, 2016