HV302DB1 Datasheet, PDF (1/2 Pages) Supertex, Inc – Hotswap Controller

HV302DB1
Hotswap Controller
Introduction
The Supertex HV302DB1 demo board contains all circuitry
necessary to demonstrate the features of the HV302
hotswap controller. Intended primarily as a negative
hotswap controller, the HV302 controls the negative supply
path. Four sequenced power-good signals are provided,
with timing controlled via 3 resistors.
Included on board is a 100+F capacitor to provide a
capacitive load for testing. Additional capacitance may be
connected to the VOUT terminals. Or the 100+F may be
removed altogether
The board may be modified to meet custom requirements.
Instructions are provided on the next page for modifications.
Specifications
Input Voltage
Inrush Limit
Circuit Breaker Trip
Retry Interval
On Resistance
Undervoltage Trip
Overvoltage Trip
Power Good Signals
PWRGD A
PWRGD B
PWRGD C
PWRGD D
Board Layout and Connections
10V to 90V
1A ±20%
6.7A ±20%
16sec typ
40m 8 max
38.0V on, 32.2V off
64.5V on, 70.0V off
Active High
~5ms after CLOAD charged
~200ms after ‘A’
~100ms after ‘B’
~5ms after ‘C’
+
+
+
+
R10
R9
HV302
R8
C6
R4
C3
DC/DC
enable ^Converter
–
DC/DC
enable ^Converter
–
DC/DC
enable ^Converter
–
DC/DC
enable ^Converter
–
C1
C2 R6 ^R7
V_IN
C4
Q1
R5
last enabled
first enabled
V_IN
Connect the supply voltage to these terminals. Supply
voltage may range from 10 volts to 90 volts.
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:
R_SOURCE
<
3V
I _LOAD
V_OUT
Connect the power supply or other load to these terminals.
VOUT+ is connected to VIN+, it is VOUT– that is switched.
Application of a DC load during start-up extends the time
inrush limiting is active. If this time exceeds 100ms, the
HV302 shuts off, retrying as quickly as 12s later. For this
rev 0 21MAY021
reason, DC load at start-up should be less than 900mA.
Note that DC start-up load limitation decreases with added
load capacitance.
Connecting additional load capacitance alters the inrush
current limit. See the HV302/312 data sheet for details.
PWRGD
Connect to the power supply’s ENABLE inputs. Depending
on the power supply, it may be necessary to level-translate
this signal via opto-isolator or discrete circuit. Refer to the
HV302/312 data sheet for a description of PWRGD and
related application circuits.
PWRGD is an open-drain output. During start-up and
whenever VIN is lower than the undervoltage trip point or
greater than the overvoltage trip point, PWRGD is pulled
down to VIN–. Once VIN is within the proper range and the
load capacitance has fully charged, PWRGD assumes a high
impedance state.
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