HT7L4661 Active PFC Non-isolation Buck LED Lighting Driver With Dimming Function Feature Applications • Non-isolation buck topology • General illumination • Wide AC input range − from 85VAC to 265VAC • E26/27, T5/T8 LED Lamp • High Power Factor of >0.9 without additional circuitry • Other LED Lighting Applications • Internal 650V high voltage JFET for quick startup General Description • Provides 5V LDO output The HT7L4661 is a Buck converter controller using quasi-resonant conversion technology. It can be used for driving high-brightness LEDs with power factor correction in off-line applications. The controller is implemented by driving an external power MOSFET and measuring and regulating a constant LED current. • Accurate constant current (< ±3%) • Includes linear dimming function • Low operating current to maximise conversion efficiency • Under-voltage lockout with hysteresis Additional features in the device include a rapid high voltage startup function and a 5V LDO output with a 1mA drive capability for external loads. There is also a linear dimming function to adjust the LED illumination level. • Full protection functions for enhanced safety –– Maximum gate drive output clamp –– VCC over voltage protection − VCC OVP –– VCC under-voltage lockout with hysteresis − VCC UVLO –– Output LED string over current protection –– Output LED string short protection –– Output LED string open protection –– CS, ZCD pins open protection –– On-chip Vver temperature protection − OTP The device also includes multiple protection features to protect it from fault conditions. These include under-voltage lockout, over-current protection, Vcc pin over-voltage protection and a ZCD pin overvoltage protection for the output voltage. Additionally, to ensure device reliability, there is also a fully integrated thermal protection function. • Small 10-pin MSOP package Application Circuits ACIN VOUT+ VOUT- 1 2 3 HV N.C DRV VSS 9 CS 7 COMP DIM 8 REG5V 6 OUT VDD 5 GND HT7L4661 4 VDD 10 ZCD Controller Rev. 1.00 1 January 26, 2015 HT7L4661 Block Diagram VCC REG5V VCC Clamping LDO HV Start-up Reference & Bias OVP1 HV UVLO Driver DRV Minimum Off Time ZCD Comparator ZCD OVP2 Logic Control OTP Starter OCP CS Linear Dimmimg PWM Generator EA Vref DIM COMP LEB GND Pin Assignment HV NC DRV VCC GND 1 10 2 9 3 8 4 7 5 6 ZCD CS DIM COMP REG5V HT7L4661 10 MSOP-A Rev. 1.00 2 January 26, 2015 HT7L4661 Pin Description Pin No. Pin Name Description 1 HV High-Voltage startup pin. The HV pin is connected to the AC line voltage to provide the charging current to the VCC capacitor. 2 NC No Connection 3 DRV Output to drive the external power MOSFET 4 VCC Internal circuitry power supply pin. Must be bypassed with a capacitor to GND with value of at least 10μF. 5 GND Ground 6 REG5V 5V LDO output. Must be bypassed with capacitor to GND with value of at least 1uF. 7 COMP Error amplifier output. A capacitor is placed between COMP and GND to provide a stable frequency response. 8 DIM Linear dimming input. Sets the current sense threshold as long as the voltage at this pin is less than 3V. 9 CS Current sense pin. A resistor is connected here for MOSFET current sensing. 10 ZCD Zero-current detect pin. Input from auxiliary winding for zero-current detection and output over-voltage sensing. Absolute Maximum Ratings VCC Supply Voltage����������������������������������������������������������������������������������������������������������������������������������� -0.3V~33V HV Voltage������������������������������������������������������������������������������������������������������������������������������������������������ -0.3V~650V DIM, CS,COMP, LDO Pins�������������������������������������������������������������������������������������������������������������������������� -0.3V~6V ZCD pin Maximum current������������������������������������������������������������������������������������������������ 3mA (source), 3mA (sink) Maximum Junction Temperature������������������������������������������������������������������������������������������������������������������������ 150°C Storage Temperature Range�������������������������������������������������������������������������������������������������������������������� -55°C~150°C 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. Recommended Operating Ranges VCC Supply Voltage������������������������������������������������������������������������������������������������������������������������������������� 17V~25V Operating Junction Temperature������������������������������������������������������������������������������������������������������������� -40°C~125°C Rev. 1.00 3 January 26, 2015 HT7L4661 Electrical Characteristics Symbol VCC=18V, Ta=25°C Parameter Test Condition Min. Typ. Max. Unit Power Supply (VCC Pin) VCCON Turn-on Threshold — — 16 — V VCCOFF Turn-off Threshold — — 8.4 — V Hys Hysteresis — 6.8 — — V VOVP OVP level on VCC pin — 26 29 32 V ISTART Start-up Current Before turn-on, VCC=11V — 45 60 μA IQ Quiescent Current No switching — — 700 μA ICC Operating Current 70kHz, CO=1nF — — 3 mA High Voltage Start-up VCCST(ON) High V section Turn-on Threshold — — 17 — V VCCST(OFF) High V section Turn-off Threshold — — 10 — V Hys Hysteresis — — 7 — V V Linear Regulator VCC LDO Input Voltage — 8 — 30 Reg5V Regulated Output Voltage — 4.5 5 5.5 V IOUT(STD) Output Current at Standby Mode VDIM < 0.4V 1 — — mA IOUT(OP) Output Current at Operating Mode VDIM > 0.4V 5 — — mA Voltage Feedback Input Threshold Tj=25°C 194 200 206 mV Error Amplifier VFB Current Sense Comparator tLEB VOCP VCL Leading Edge Blanking Time — — 400 — ns Over Current Protection Threshold — — 0.9 — V Over Current Release Threshold — — 0.2 — V Current Limit Threshold — — 1.3 — V — 3 — V Zero Current Detector VZCDH Upper Clamp Voltage IZCD=300μA VZCDL Lower Clamp Voltage IZCD=-2.5mA — -0.2 — V VZCDA Positive-Going Edge — — 1.5 — V VZCDT Negative-Going Edge — — 1 — V IOVP ZCD pin OVP current level — 285 300 315 μA tB_OVP OVP Detection Blanking Time — tSTART Start Timer Period — — 40 — μs tOFF Minimum Off Time — — 4 — μs Over Temperature Lockout — — 150 — °C Over Temperature Resume — — 110 — °C 1 μs Starter Over Temperature Protection OTP Gater Driver tR Rise Time Co=1nF, 10%~90% — 100 — ns tF Fall Time Co=1nF, 10%~90% — 70 — ns VCLAMP Gate Clamp Voltage VCC=25V — — 19.5 V Dimming VDIM Linear Dimming Range — 0.4 — 3 V Vsat Saturation Threshold Voltage — — 3 — V Vled(off) LED Current off Threshold Voltage — — 0.4 — V Note: These Parameters, although guaranteed, are not 100% tested in production. "*" Suggest to limit switching frequency under 75kHz for Green Mode operation. Rev. 1.00 4 January 26, 2015 HT7L4661 Typical Performance Characteristics 60 Operating Current (μA) Start-up Current (μA) 55 50 45 40 35 30 25 -40 -20 0 20 40 60 Temperature (℃) 80 100 120 -40 0 20 40 60 Temperature (℃) 80 100 120 Figure 2. Operation current vs. temperature 17.0 8.5 16.9 8.4 16.8 8.3 16.7 8.2 16.6 16.5 16.4 16.3 8.1 8.0 7.9 7.8 16.2 7.7 16.1 7.6 16.0 -40 -20 0 20 40 60 Temperature (℃) 80 100 7.5 120 -40 Figure 3. UVLO_on vs. temperature 18.0 11.0 17.9 10.8 17.8 10.6 17.7 10.4 17.6 17.5 17.4 17.3 20 40 60 Temperature (℃) 80 100 9.0 120 Figure 5. UVLO(st)_on vs. temperature Rev. 1.00 100 120 9.6 9.2 0 80 9.8 9.4 -20 20 40 60 Temperature (℃) 10.0 17.1 -40 0 10.2 17.2 17.0 -20 Figure 4. UVLO_off vs. temperature UVLO(st)_off (V) UVLO(st)_on (V) -20 Figure 1. Start-Up current vs. temperature UVLO_off (V) UVLO_on (V) 20 800 775 750 725 700 675 650 625 600 575 550 525 500 -40 -20 0 20 40 60 Temperature (℃) 80 100 120 Figure 6. UVLO(st)_off vs. temperature 5 January 26, 2015 VFB (mV) 5.20 Operating Mode LDO Voltage (V) Standby Mode LDO Voltage (V) HT7L4661 5.15 5.10 5.05 5.00 4.95 4.90 4.85 4.80 206 205 204 203 202 201 200 199 198 197 196 195 194 -40 -20 0 20 40 60 Temperature (℃) 80 100 120 5.20 5.15 5.10 5.05 5.00 4.95 4.90 4.85 4.80 -40 -20 0 20 40 60 Temperature (℃) 80 100 120 Figure 7. LDO Voltage Figure 8. LDO Voltage (Operating Mode) vs. (Standby Mode) vs. Temperature Temperature -40 -20 0 20 40 60 Temperature (℃) 80 100 120 Figure 9. VFB vs. Temperature Rev. 1.00 6 January 26, 2015 HT7L4661 Functional Description The HT7L4661 is a universal AC/DC LED driver designed for LED lighting applications. The device can achieve high Power Factor values without resorting to additional external circuity and can also generate high accuracy LED drive currents with very few external components. Separate grounds are provided; one is a floating ground for the HT7L4661 while the other one is for ground. It is important to note that the two grounds cannot be directly connected together to avoid IC damage and system malfunction. Zero Current Detection − ZCD The ZCD voltage is designed to operate between 0V and 3V for normal operation. If the voltage on the ZCD pin ���������������������������������������� increases������������������������������� higher than 1.5V, the ZCD comparator waits until the voltage falls below 1V. When the inductor current is at the zero crossing point, the voltage on the ZCD pin will drop rapidly. The device will then detect the 1V falling edge and turn on the Power MOSFET. The 0.5V of hysteresis avoids any false triggering actions due to noise. High Voltage Start-up Constant Current Control Due to its internal high-voltage startup circuit, when an AC voltage is applied to the power system, the device provides a high current to charge the external Vcc capacitor to speed up the system startup time. To save power consumption, after the Vcc voltage has exceeded the turn-on voltage and enters normal operation, the high-voltage startup circuit is shutdown. The device will sense the overall inductor current and form a closed-loop with an internal error amplifier to obtain high constant current accuracy. The CS voltage and the 0.2V reference voltage form the inputs to a Gm amplifier whose output is integrated using an external C������������������������������������������������ OMP��������������������������������������������� capacitor. The ����������������������������� ON��������������������������� time of ������������������ the �������������� MOSFET is controlled by the COMP voltage to adjust the LED current. VCC Under Voltage Lockout − UVLO Leading-Edge Blanking − LEB on CS The device includes a UVLO feature which includes a 6.8V hysteresis value. The PWM controller turns on when VCC is higher than 16V and turns off when VCC is lower than 8.4V. The hysteresis characteristics guarantee that the device can be powered by an input capacitor during start-up. When the output voltage increases to a certain value after start-up, VCC will be charged by an output through an auxiliary winding or a Zener Diode. VZ=VLED-VCC. Each time the external power MOSFET is switched on, a turn-on spike will inevitably occur at the sense resistor. To avoid faulty triggering, a 400ns leadingedge blank time is generated. As this function is provided c�������������������������������������������� onventional RC filtering ������������������� is therefore ������ unnecessary. During this blanking period, the current-limit comparator is disabled and can therefore not switch off the gate driver. Low Dropout Regulator − LDO Gate Driver Clamp A low dropout regulator (LDO) is included in the device and provides a stable 5V output voltage for other devices. When the dim voltage is lower than 0.4V, the LDO obtains its power from the high voltage start-up circuit and the drive current of LDO is 1mA. During normal operation, VCC will be charged by an output�������������������������������������������� ������������������������������������������� through ����������������������������������� an �������������������������������� auxiliary winding or ����������� a ��������� Zener Diode. Thus, the driving current of LDO can increase to 5mA. The DRV pin is connected to the gate of external MOSFET ��������������������������������������� to control its ON/OFF function��������� .�������� ������� To protect the external power MOSFET from being overstressed, the gate driver output is clamped to 17V. Over Voltage Protection − OVP on VCC In order to prevent PWM controller damage, the device includes an OVP function for VCC. Should the VCC voltage �������������������������������������� be������������������������������������ higher than the OVP threshold voltage of 29V, the PWM controller will stop operation immediately. When the VCC voltage decreases below the UVLO off level, the controller will reset. Boundary Conduction Mode − BCM The power MOSFET is turned on by inductor current zero-crossing detector. The current zero-crossing can be detected by ������������������������������������� a ����������������������������������� ZCD voltage������������������������ .����������������������� When ����������������� the ������������� inductor current is at the zero crossing point, the voltage on the ZCD pin will drop rapidly. The device then detects the falling edge and turns on the Power MOSFET. The boundary conduction mode provides low turn-on switching losses and high conversion efficiency. Rev. 1.00 7 January 26, 2015 HT7L4661 LED Open Protection − ZCD OVP Thermal Protection The LED voltage is reflected on the ZCD pin through a resistor RZCD. When the current through the RZCD resistor is higher than 300μA, then ZCD OVP protection will take place��������������������� and ���������������� the PWM controller will stop operation immediately. When the VCC voltage �������������������������������������������� decreases below ���������������������������� the ������������������������ UVLO off level, the controller will reset. A thermal protection feature is included to protect the device������������������������������������������� from excessive heat damage. When the junction temperature exceeds a threshold of 150°C, the thermal protection ����������������������������������� function �������������������������� will turn off the DRV terminal immediately. When the VCC decreases below the UVLO off level, the controller will reset. Dimming Function VOVP-ZCD can be set using the following equation: On the DIM pin, when the voltage on this pin is lower than 0.4V, the device output driving operation will be shut down and the LED current will reduce to zero for this condition. When the voltage is between 0.4V and 3V, the device will be operating in its linear dimming range and the LED current will be controlled according to the pin voltage. While the pin voltage is higher than 3V, the device will operate in its normal operating condition. VOVP − ZCD = VZCDH + IOVP × R ZCD The VZCDH is the upper clamp voltage of 3V on the ZCD pin. The IOVP represents the OVP current level on the ZCD pin which is 300μA. RZCD stands for the resistor connected between the ZCD pin and the LED positive terminal. Over Current Protection − OCP The ������������������������������������������������ device������������������������������������������ includes an over current protection function on������������������������������������������������� the��������������������������������������������� CS pin. An internal circuit detects the current level and when the current is larger than the over current protection threshold level, VOCP/RCS, the gate output will remain at a low level. Standby Mode Range Iout(%) 100 LED Short Protection − SCP The output voltage drops when a number of LEDs in a string are shorted resulting in a voltage drop at VCC. Once the VCC drops below 8.4V, the device will stop operating. Under such situations, the start-up operation will recharge the VCC pin through the startup resistor and the device will enter the UVLO hiccup mode. Rev. 1.00 Saturation Range 13.3 0.4 8 Linear Dimming Range Vdim(V) Iout 3 January 26, 2015 HT7L4661 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 9 January 26, 2015 HT7L4661 10-pin MSOP Outline Dimensions Symbol Nom. Max. A — — 0.043 A1 0.000 — 0.006 A2 0.030 0.033 0.037 B 0.007 — 0.013 C 0.003 — 0.009 D — 0.118 BSC — E — 0.193 BSC — E1 — 0.118 BSC — e — 0.020 BSC — L 0.016 0.024 0.031 L1 — 0.037 BSC — y — 0.004 — θ 0° — 8° Symbol Rev. 1.00 Dimensions in inch Min. Dimensions in mm Min. Nom. Max. A — — 1.10 A1 0.00 — 0.15 A2 0.75 0.85Q 0.95 B 0.17 — 0.33 C 0.08 — 0.23 D — 3.00 BSC — E — 4.90 BSC — E1 — 3.00 BSC — e — 0.50 BSC — L 0.40 0.60 0.80 L1 — 0.95 BSC — y — 0.10 — θ 0° — 8° 10 January 26, 2015 HT7L4661 Copyright© 2015 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. Rev. 1.00 11 January 26, 2015