HV9911DB4 Supertex, HV9911DB4 Datasheet - Page 2

• Manufacturer Part Number: HV9911DB4
• Manufacturer: Supertex

Specifications of HV9911DB4

• Lead Free Status / Rohs Status: Not Compliant

Demoboard Testing:
Normal Operation: Connect the input source and the output
LEDs as shown in the connection diagram and enable the
board. The LEDs will glow with a steady intensity. Connecting
an ammeter in series with the LEDs will allow measurement
of the LED current. The current will be 700mA +/- 5%.
Current Regulation: With the input power to the converter
disconnected, change the input voltage or the LED string
voltage within the specifications mentioned. The current
output of the HV9911DB4 will remain very steady over the
entire line range.
With the supply turned off, change the LED string voltage
within the specified limits and turn the power supply back on.
The current will still be regulated at around 700mA.
Open LED test: Connect a voltmeter across the output
terminals of the HV9911DB4. Start the demoboard normally
and once the LED current reaches a steady state, unplug
one end of the LED string from the demoboard. The output
voltage will rise to about 30V and the HV9911DB4 will shut
down. To restart the converter, disconnect and reconnect the
input voltage (recycle the power to the board).
Short Circuit Test: When the HV9911DB4 is operating in a
steady state, connect a jumper across the terminals of the
LED string. Notice that the output current will immediately
go to zero and the converter will shut down. To restart the
HV9911DB4, recycle the input power to the demoboard.
PWM Dimming: With the input voltage to the board
disconnected, apply a TTL-compatible, push-pull square
wave signal between PWMD and GND terminals of
connector J3 as shown in the connection diagram. Turn
the input voltage back on and adjust the duty cycle and/or
frequency of the PWM dimming signal. The output current
will track the PWM dimming signal. Note that although the
converter operates perfectly well at 1kHz PWM dimming
frequency, the best PWM dimming ratio can be obtained at
lower frequencies, like 100Hz or 200Hz.
Typical Results
1. Efficiency: The efficiency of the converter at various LED
string voltages are shown in Fig.1 (measured at the nominal
input voltage of 24V). Fig.2 shows the full load efficiency
of the converter at varying input voltages. The minimum
efficiency of 68% for the converter occurs at minimum load
voltage.
Supertex inc.
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1235 Bordeaux Drive, Sunnyvale, CA 94089
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2. Current Regulation: Fig.3 and Fig.4 show the output
current regulation vs. load voltage and input voltage
respectively.
combined) is less than 1%.
90
85
80
75
70
65
88
87
86
85
84
83
82
0.705
0.700
0.695
0.710
0.690
0.705
0.700
0.695
0.710
0.690
Fig.3 Output Current vs. Output Voltage
3
9
Fig.4 Output Current vs. Input Voltage
Fig.1 Efficiency vs. Output Voltage
Fig.2 Efficiency vs. Input Voltage
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3
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Efficiency vs. Load Voltage (V
The total current regulation (line and load
Full Load Efficiency vs. Input Voltage
8
Load Regulation (V
11
Line Regulation (V
8
11
Output Voltage (V)
Input Voltage (V)
Output Voltage (V)
Input Voltage (V)
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www.supertex.com
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13
13
IN
O
= 13.5V)
HV9911DB4
= 24V)
IN
18
= 13.5V)
18
15
15
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