Supertex inc.
Off-Line, High Brightness, 1.4A
LED Driver Demo Board
General Description
The HV9910BDB1
demoboard is an offline, high current
LED driver designed to drive a 40V LED string at 1.4A from
a 110V input. The demoboard uses Supertex’s HV9910B
LED driver IC to drive a buck converter.
The HV9910BDB1 has a typical full load efficiency of 88%,
with the buck converter efficiency (excluding the diode
bridge rectifier and EMI filter) at 93%. The demoboard also
meets CISPR-15 conducted EMI standards.
The output current can be adjusted in two ways - either
with linear dimming using the onboard potentiometer or
with PWM dimming by applying a TTL-compatible square
wave signal at the PWMD terminal. Using linear dimming,
the output current of the HV9910DB1 can be lowered to
about 0.1A (note: zero output current can be obtained only
by PWM dimming).
HV9910BDB1
Specifications
Input voltage
Output voltage
Output current
Output current ripple (typ)
Full load efficiency (@110V)
Power factor (@110V)
Input current (@110V)
Input current THD (@110V)
Switching frequency (typ)
Minimum output current (@110V)
Conducted EMI
Temperature rise of heatsink
(@110V input and full load)
Open LED protection
Output short circuit protection
Dimensions
90 - 135Vrms, 50/60Hz
10 - 40V
1.4A max
40% (peak-peak)
88%
0.64
0.83A rms
117%
50kHz
0.1A
Meets CISPR-15
50°C
yes
no
86.4mm X 58.4mm
Connection Diagram
10 - 40V, 1.4A max.
90 - 135VAC
50/60Hz
WARNING!!!
Do not connect earth-grounded test instruments. Doing so will short the AC line, resulting in damage to the
instrument and/or the HV9910BDB1. Use floating high voltage differential probes or isolate the demoboard
by using an isolating transformer.
There is no galvanic isolation. Dangerous voltages are present when connected to the AC line.
Doc.# DSDB-HV9910BDB1
A032813
Supertex inc.
www.supertex.com
HV9910BDB1
Connections
1. Connect the input AC voltage between the AC IN terminals as shown in the connection diagram.
2. Connect the LED string between LED+ (anode of LED string) and LED- (cathode of LED string).
3. Connect the PWMD terminal to the VDD terminal using the jumper provided to enable the LED driver.
4. The current level can be adjusted using the on-board potentiometer.
PWM Dimming
The HV9910BDB1
is capable of being PWM dimmed by applying a square wave TTL compatible signal between PWMD
and GND terminals. However, since there is no galvanic isolation on the board, care must be taken to prevent damage to
the PWM dimming source and/or the HV9910BDB1. One simple way is to isolate the LED driver from the AC line using an
isolation transformer. Another approach is to use an opto-isolator to drive the PWMD pin as shown in the figure below.
3.8k
5.0V
square wave signal
(<1.0kHz)
Opto-isolator
(eg: LTV-814 from Lite-On)
VDD
PWMD
Typical Results
89
Full Load Efficiency vs. Input Voltage
90
Efficiency vs. Load Voltage (@V
IN
=110V rms)
86
Efficiency (%)
87
86
Efficiency (%)
88
82
78
90
100
110
120
130
140
74
5
15
25
Load Voltage (V)
35
45
Input Voltage (Vrms)
5
Line Regulation of Load Current
15
12.5
10
7.5
5
2.5
0
Load Regulation of Load Current
(@ V
IN
= 110V rms)
Change in output current (%)
2.5
0
-2.5
-5
90
100
110
120
130
140
Change in output current (%)
5
15
25
Load Voltage (V)
35
45
Input Voltage (Vrms)
Doc.# DSDB-HV9910BDB1
A032813
2
Supertex inc.
www.supertex.com
Test/Measurement
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