Data Sheet

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. 1.10
1
January 19, 2015
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. 1.10
1
2
Top View
January 19, 2015
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. 1.10
-40°C~125°C
3
January 19, 2015
HT7L5600
Electrical Characteristics
Symbol
(VCC=12V, Ta=25°C)
Parameter
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
50
—
ns
Starter
Over Temperature Protection
OTP
Over Temperature Trip Point
Gate Driver
tR
Rising Time
CLOAD=1nF, 10%~90%
—
tF
Falling Time
CLOAD=1nF, 10%~90%
—
50
—
ns
ISource
Source Current
—
—
300
—
mA
ISink
Sink Current
—
—
300
—
mA
VG_CLAMP
Gate Clamp Voltage
@ VCC = 20V
—
16
19.5
V
Rev. 1.10
4
January 19, 2015
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. 1.10
-20
Figure 8. Iout vs. LED Series
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January 19, 2015
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. 1.10
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.
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January 19, 2015
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. 1.10
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January 19, 2015
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. 1.10
8
January 19, 2015
HT7L5600
SOT23-6 Outline Dimensions
Symbol
A
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°
Symbol
Rev. 1.10
Dimensions in inch
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°
9
January 19, 2015
HT7L5600
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.tw.
Rev. 1.10
10
January 19, 2015