SUPERTEX HV100DB1

HV100 Demo Board
HV100DB1
3-Pin Hotswap Controller
Introduction
Specifications
The Supertex HV100DB1 demo board contains all necessay
circuitry to demonstrate the features of the HV100 hotswap
controller. Intended primarily as a negative hotswap controller,
the HV100 controls the negative supply path.
Input Voltage
10V to 72V
Peak Inrush Limit
1.4A typ
Max Short Circuit Current1
Included on board is a 100µF capacitor (C3) to provide a
capacitive load for testing. Additional capacitance may be
connected to the VOUT terminals. Or the 100µF may be removed
altogether
The board may be modified to meet custom requirements.
Instructions are provided on the next page for modifications.
4A typ
Circuit Breaker Response Time1
1ms typ
Auto Retry
2.5s typ
On Resistance
Undervoltage Trip
1
210mW_ max
37V on, 34V off
During inrush limiting
Board Layout and Connections
+OUT
VPP IN
VPP
OUT
VIN
Current
Probe
C2
C1
R2
alt Q1
VNN IN
U1
+
C3
DRAIN
GATE
VOUT
Power Supply
or Load
-OUT
Q1
R1
VIN
VOUT
Connect the supply voltage to these terminals. Supply voltage
may range from 10 volts to 72 volts.
Connect the power supply or other load to these terminals. VOUT+
is connected to VIN+, it is VOUT– that is switched.
A high source impedance may cause oscillations when the input
voltage is near the undervoltage trip point. A high source
impedance results in a large voltage drop when loaded, causing
undervoltage lockout to kick in, disconnecting the load. With the
load removed, input voltage rises, causing undervoltage to
release and reconnecting the load. The cycle repeats, resulting
in oscillations. Source impedance must be less than the following to avoid oscillations:
Application of a DC load during start-up and/or additional load
capacitance extends the time inrush limiting is active. If this time
exceeds 100ms, the HV100 shuts off, retrying 2.5s later. For this
reason, DC load at start-up should be less than 900mA. Note
that DC start-up load limitation decreases with added load
capacitance.
RSOURCE =
Note that the circuit breaker functions during inrush only.
1.5V
I LOAD
01/21/02
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability
indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to
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workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications
are subject to change without notice. For the latest product specifications, refer to the
Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.
HV100 Demo Board
HV100 Demo Board Schematic
VPP OUT
VPP IN
OUT+
VPP
HV100
VNN
GATE
C2
not used
VNN IN
current
probe
C1
not used
GATE
C3
100µF
R2
not used
OUTQ1
IRFR120N
R1
0Ω
A very high dV/dt on the input can overload the HV100’s internal
gate clamp, causing turn-on transients. A capacitor in the C2
position may be used to clamp the gate, preventing the transients. A 1nF value is usually adequate. Voltage rating should be
16 volts.
DRAIN
To reduce peak inrush current, a capacitor from gate to drain (C1)
may be employed. A resistor (R2) is also needed in this configuration for loop stability. Please refer to the HV100 data sheet for
further information.
Note: When making positive-ground measurements, scope
probe loading on the GATE pin may interfere with normal
operation. To observe gate voltages, use negative-ground measurements.
To limit short-at-turn-on current, zero-ohm resistor R1 may be
replaced with a low value resistor. This resistor causes a voltage
drop that tends to cancel-out the applied gate voltage, thus
limiting drain current.
01/21/02
©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
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1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 • FAX: (408) 222-4895
www.supertex.com