HV9921DB1 Supertex, HV9921DB1 Datasheet

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HV9921DB1

Manufacturer Part Number
HV9921DB1
Description
Manufacturer
Supertex
Datasheet
1.HV9921DB1.pdf (2 pages)

Specifications of HV9921DB1

Lead Free Status / RoHS Status
Not Compliant
Introduction
The Supertex HV9921DB1 demoboard is a complete LED
power driver to supply a string of LEDs using the HV9921,
an integrated 3-pin high input voltage constant-current
buck regulator IC. The HV9921 integrates a 500V switching
MOSFET and can operate directly from the rectified universal
AC line voltage range of 80 to 265VAC.
The current in the LED string is internally programmed to
20mA ±15%. The HV9921DB1 is ideally suited for driving
strings of LEDs having forward voltage from 20 to 50V at
high efficiency (typically 80% at 120VAC).
The HV9921DB1 is a peak current-controlled buck converter
operating with fixed off-time of 10.5us. Its fixed off-time
control scheme provides good stability and tight regulation of
the LED current throughout the input AC line voltage range.
As its switching frequency varies over the AC line cycle, the
HV9921 inherently introduces frequency dither and simplifies
the compliance with EMI regulations.
Board Layout and Connection Diagram
Connections
LED+: Connect the Anode of the LED string to this pin.
LED-: Connect the Cathode of the LED string to this pin.
AC1, AC2: Connect AC Line to these pins.
LED String
V
I
F
F
= 20mA
= 20 to 50V
LED+
LIN
LED-
C0
CIN2
D1
●
1235 Bordeaux Drive, Sunnyvale, CA 94089
LED Driver Demoboard
D4
D2
CIN
Universal Off-line
U1
L1
D5
HV9921
CDD
C2
D3
+
Specifications
Note:
Parameter
Input voltage range
Load current
LED string voltage
Conducted EMI
Efficiency
AC Line
80 - 265VAC
The demoboard is not protected from output open/
short circuit condition. Damage to the demoboard may
occur if the output load is not properly connected.
●
Tel: 408-222-8888
●
www.supertex.com
HV9921DB1
80 to 265VAC
20mA ± 15%
CISPR15
20 ~ 50V
80% typ.
Value

HV9921DB1 Summary of contents

Page 1

... MOSFET and can operate directly from the rectified universal AC line voltage range 265VAC. The current in the LED string is internally programmed to 20mA ±15%. The HV9921DB1 is ideally suited for driving strings of LEDs having forward voltage from 20 to 50V at high efficiency (typically 80% at 120VAC). ...

Page 2

... Connect the AC input to the input terminals. Apply the AC voltage at the input terminals and the LED string should start to glow. The HV9921DB1 will regulate constant 20mA current in the LED. Schematic Diagram D2 ...