Supertex inc.
Supertex inc.
www.supertex.com
HV9922DB2
Doc.# DSDB-HV9922DB2
A032913
General Description
The HV9922DB2 is a universal input, ofine, non-isolated
auxiliary power supply using Supertex’s HV9922 constant
current switching regulator IC. The output voltage is
regulated to 23V +/-5% and is referenced to the negative
side of the diode bridge rectier (i.e. ground of the rectied
DC voltage). The demoboard is protected against output
open circuit and short circuit conditions and meets FCC
Class B (residential) EMI limits.
The HV9922 acts as a constant 50mA current source which
is sourced into an output zener diode. On the demoboard, a
22V zener diode is used at D2 to regulate the output voltage
to 23V within +/-5%. Lower output voltages can be obtained
by using an appropriate 2W zener diode in parallel to D2 in
the space provided on the demoboard (D3).
Board Layout and Connection Diagram
Ofine, Non-Isolated, 23V, 45mA
Auxiliary Power Supply
Specications
Parameter Value
Input voltage: 85 - 265VAC, 50/60Hz
Output voltage: 23V +/-5%
Output current: 0 - 45mA
Switching frequency: variable
Full load efciency: 50% (at 110V input),
44% (at 220V input)
Open circuit voltage: 24V
Output short circuit protection: Included
Dimensions: 53.4mm x 38.2mm
Connections:
Input: Connect the input AC voltage between AC1 and AC2
as shown.
Output: Connect the output load between VO+ and VO- as
shown. An ammeter and voltmeter can be connected as
shown to measure the output voltage and load current if
desired.
WARNING: Do not use earth grounded test instruments or
loads! Doing so will short the AC line, resulting in damage
to the instrument, load and/or the HV9922DB2. Use an iso-
lated supply or high voltage differential probes when testing
the circuit.
There is no galvanic isolation. Dangerous voltages are pres-
ent when connected to the AC line.
+A
85 - 265VAC, 50/60Hz
+
V