HT7L5600 Primary side regulation off line LED driver with active PFC Features General Description • Small outline SOT23-6 package The HT7L5600 is a single-stage, isolated, primaryside offline LED lighting controller that achieves a high power factor. Power control is implemented by controlling an external MOSFET and accurate LED constant current regulation from the primary-side information. This can significantly simplify the LED lighting system design by eliminating the secondaryside feedback components and the normally required opto-coupler. The extremely low start-up current and quiescent current reduces the total power consumption to provide a high efficiency solution for lighting applications. • Primary-side current sensing and regulation without an opto-coupler • Wide AC input range – from 85VAC to 265VAC • High Power Factor of >0.9 without additional circuitry • Accurate constant current (< ±3%) • Low start-up current which reduces power dissipation • Full protection functions for enhanced safety: ♦♦ Gate driver output voltage 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 / open protection ♦♦ On-chip over temperature protection – OTP The HT7L5600 provides several protection functions, which include VCC Under Voltage Lockout (UVLO), Over Current Protection (OCP), Output LED String Open Protection, Output LED String Short Protection, VCC Over Voltage Protection (OVP) and LeadingEdge Blanking (LEB) for current sensing. Additionally and to ensure system reliability, the device includes a fully integrated thermal protection function. To protect the external power MOSFET from being damaged by an over voltage, the device DRV pin voltage is clamped to about 16V. Applications • General illumination • E26/27, T5/T8 LED Lamp The high level of functional integration minimises the external component count giving major advantages in terms of cost and circuit board area. The device is supplied in a SOT23-6 package. • Other LED Lighting Applications Application Circuits ACIN VOUT+ VOUT- COMP ZCD GND VCC CS DRV HT7L5600 Rev. 1.00 1 December 19, 2014 HT7L5600 Block Diagram DRV VCC Reference & Bias UVLO Driver Min Off Time VCC OVP ZCD ZCD Comparator Logic Control ZCD OVP OTP Starter OCP CS S&H PWM Generator EA 0.3V COMP LEB GND Pin Assignment SOT23-6 ZCD VCC DRV 6 5 4 L5600 2 3 COMP GND CS Rev. 1.00 1 2 Top View December 19, 2014 HT7L5600 Pin Description Pin No. Symbol 1 COMP Description 2 GND 3 CS 4 DRV Gate drive output for driving external power MOSFETs 5 VCC Power supply pin 6 ZCD Connected to a resistor divider from the auxiliary winding to sense the output voltage. Loop compensation pin. A capacitor should be placed between COMP and GND. Ground pin Current sense pin. A resistor is connected to sense the MOSFET current. Absolute Maximum Ratings Parameter Range VCC supply voltage -0.3V~27V Input voltage to CS pin -0.3V~6V Output voltage at COMP pin -0.3V~6V Maximum current at ZCD pin 3mA (source), 3mA (sink) Maximum operating junction temperature 150°C Storage temperature range -55°C~150°C Recommended Operating Ranges Parameter Range VCC Supply voltage 10V~20V Operating junction temperature Rev. 1.00 -40°C~125°C 3 December 19, 2014 HT7L5600 Electrical Characteristics Symbol Parameter (VCC=12V, Ta=25°C) Test Condition Min Typ Max Unit Power Supply (VCC Pin) VCCON UVLOON — — 18 — V VCCOFF UVLOOFF — — 7.5 — V VCCHYS UVLO Hysteresis — 10 — — V VOVP1 VCC OVP Trip Point — 21.5 24 26.5 V — 10 20 μA ISTART Start-up Current Before turn-on, @VCC=UVLOON - 1V IQ Quiescent Current No switching — 0.7 1 mA ICC Operating Current @70kHz, Co=1nF — 1.3 2 mA 291 300 309 mV Error Amplifier VFB Feedback Reference Voltage Ta=25°C Current Sense Comparator TLEB Leading Edge Blanking Time — — 400 — ns VOCP Current Limit Threshold — — 1.55 — V VSCP ZCD Pin Short Circuit Protection Threshold — — 0.4 — V V Zero Current Detector VZCDH Upper Clamp Voltage IZCD=2.5mA — 6.1 — VZCDL Lower Clamp Voltage IZCD= -2.5mA — -0.7 — V VZCDA Positive-Going Edge — — 150 — mV VZCDT Negative-Going Edge — — 50 — mV VOVP2 ZCD pin OVP Level — 2.88 3.2 3.52 V TB_OVP OVP Detection Blanking Time — — 1 — μs TSTART Start Timer Period — — 40 — μs TOFF Minimum Off Time — — 6.4 — μs — — 150 — °C — ns Starter Over Temperature Protection OTP Over Temperature Trip Point Gate Driver TR Rising Time CLOAD=1nF, 10%~90% — 50 TF Falling Time CLOAD=1nF, 10%~90% — 50 — ns VG_CLAMP Gate Clamp Voltage @VCC=20V — 16 19.5 V Rev. 1.00 4 December 19, 2014 HT7L5600 16 1.6 14 1.5 operating current (mA) 1.4 12 1.3 10 1.2 8 1.1 6 4 -40 -20 0 20 40 60 tem perature (℃ ) 80 100 1 0.9 -40 120 20 40 60 tem perature (℃ ) 80 100 19 8.4 18.6 8 18.2 17.8 17.4 -20 0 20 40 60 tem perature (℃ ) 80 100 7.2 6.8 6.4 -40 120 120 7.6 Figure 3. UVLO_on vs. temperature -20 0 20 40 60 tem perature (℃ ) 80 100 120 Figure 4. UVLO_off vs. temperature 26 3.5 25.5 3.4 25 24.5 ZCD_OVP (V) VCC_OVP (V) 0 Figure 2. Operation current vs. temperature 17 -40 24 23.5 23 3.3 3.2 3.1 3 22.5 22 -40 -20 0 20 40 60 tem perature (℃ ) 80 100 2.9 -40 120 Figure 5. VCC_OVP vs. temperature VFB (mV) -20 Figure 1. Start-up current vs. temperature UVLO_off (V) UVLO_on (V) start up current (uA) Typical Performance Characteristics 309 308 307 306 305 304 303 302 301 300 299 298 297 296 295 294 293 292 291 -40 -20 0 20 40 60 tem perature (℃ ) 80 100 0 20 40 60 tem perature (℃ ) 80 100 120 Figure 6. ZCD_OVP vs. temperature 120 Figure 7. VFB vs. temperature Rev. 1.00 -20 Figure 8. Iout vs. LED Series 5 December 19, 2014 HT7L5600 Figure 10.Power Factor(PF) vs. AC Voltage Figure 9. Efficiency vs. AC Voltage Functional Description VCC Under Voltage Lockout – UVLO The HT7L5600 is a single-stage primary-side offline LED controller designed for isolated LED lighting applications. The device can achieve high Power Factor values and low THD values without resorting to additional circuits and can also generate high accuracy LED drive currents with very few external components. The device has an integrated UVLO function which includes 10V of hysteresis. The PWM controller will switch on when the VCC voltage exceeds 18V. It will switch off when the VCC voltage is less than 7.5V. The hysteresis characteristics will ensure 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. Start-up Current A very low start-up current, ISTART, allows users to select a larger start-up resistor value which reduces power dissipation. Boundary Conduction Mode – BCM The power MOSFET is turned on by inductor current zero-crossing detection. 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 HT7L5600 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. Power Factor Correction High power factor is achieved by constant on-time operation. To implement constant on-time control, a 0.47µF capacitor is placed between the COMP pin and ground. Constant Current Control The HT7L5600 accurately regulates the LED current by sensing the primary-side information. The LED current can be set as follows: I OUT ≈ Leading-Edge Blanking – LEB on CS At each turn on time of the external power MOSFET, a spike will inevitably be generated at the sense resistor. To prevent faulty triggering, a 400ns leading-edge blank time will be generated. During this blanking period, the current-limit comparator is disabled and will therefore not be able to switch off the gate driver. 1 VFB N P × × 2 RCS N S Where N P is the primary winding and N S is the secondary winding; V FB(=300mV) is the internal voltage reference and R CS is the external current sensing resistor. Rev. 1.00 Gate Driver Clamp The DRV pin is connected to the gate of external MOSFET to switch it on and off. To protect the external power MOSFET from being over-stressed, the gate driver output is clamped to 16V. 6 December 19, 2014 HT7L5600 Over Voltage Protection – OVP on VCC Over Current Protection – OCP In order to prevent PWM controller damage, the device includes an OVP function for VCC. Should the VCC voltage exceed the OVP threshold voltage of 24V, the PWM controller will cease operation immediately. When the VCC voltage falls below the UVLO off level, the controller will reset. The HT7L5600 includes a CS pin over current protection function. An internal circuit detects the current level and should the current be larger than the over current protection threshold level, the gate output will then be fixed to a low level. LED Short Protection – SCP LED Open Protection – ZCD OVP The output voltage drops when a number of LEDs in a string are shorted resulting in a voltage drop on VCC. Once VCC falls below 7.5V, the device will cease operation. 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. The ZCD pin voltage is set by a resistor divider RTOP (top resistor), RBOT (bottom resistor) and an auxiliary winding due to the coupling polarity between the auxiliary winding and the secondary winding of the transformer. Once the ZCD voltage exceeds 3.2V after a blanking time about 1us to allow the leakage inductance ringing to be fully damped, ZCD OVP is triggered. The device will then stop switching but it can be reset by re-starting the voltage on the VCC pin. The OVP voltage can be adjusted by the equation: VOUT _ OVP = 3.2 × (1 + Thermal Protection 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. RTOP N ) × S + VD RBOT NA Where N S is the secondary winding, N A is the auxiliary winding and VD is the forward bias voltage of the secondary diode. Rev. 1.00 7 December 19, 2014 HT7L5600 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 8 December 19, 2014 HT7L5600 SOT23-6 Outline Dimensions Symbol A Rev. 1.00 Dimensions in inch Min. Nom. Max. — — 0.057 A1 — — 0.006 A2 0.035 0.045 0.051 b 0.012 — 0.020 C 0.003 — 0.009 D — 0.114 BSC — E — 0.063 BSC — e — 0.037 BSC — e1 — 0.075 BSC — H — 0.110 BSC — L1 — 0.024 BSC — θ 0° — 8° 9 December 19, 2014 HT7L5600 Symbol Rev. 1.00 Dimensions in mm Min. Nom. Max. A — — 1.45 A1 — — 0.15 A2 0.90 1.15 1.30 b 0.30 — 0.50 C 0.08 — 0.22 D — 2.90 BSC — E — 1.60 BSC — e — 0.95 BSC — e1 — 1.90 BSC — H — 2.80 BSC — L1 — 0.60 BSC — θ 0° — 8° 10 December 19, 2014 HT7L5600 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 11 December 19, 2014