H
OLD
U
P
M
ODULE
2. N
ORMAL
O
PERATION
Normal operation continues with the capacitor charged and the
input line voltage between 18 and 40 VDC. During this time, the
converter will operate from the line voltage through the external
diode. When the external capacitor reaches its final charge of 40
volts, the HUMMER module enters an idle state, consuming only
enough power to keep the capacitor charged. Idle state power for
the module is approximately 1 watt.
Note: The HUMMER module itself can sustain continuous voltages
of up to 50 VDC and voltage spikes of 80 volts for up to 50
msec, and it will pass these voltages on to the converter through
the external bypass diode. If these ratings exceed the rating of
the converter, care should be taken to control the line voltage to
prevent damage to the converter.
Normal Operation will continue indefinitely until the input voltage
drops below 18 VDC.
HUMMER SERIES
40 OR 70 WATTS
3. L
OW
L
INE
O
PERATION
Low line operation occurs when the input voltage drops to a range
between 18 and 12 volts. When the voltage reaches 18 VDC, the
HUMMER module’s VCS closes and then operates in a boost
mode. In this mode, the HUMMER module supplies 40 VDC
through VCS to the converter, and at the same time maintains the
charge on the capacitor. The module will operate indefinitely in this
low line region until the input line voltage drops below 12 VDC.
4. P
OWER
F
AIL
O
PERATION
When the input line voltage drops to 12 VDC, the Power Fail flag
is asserted (pulled low) and the HUMMER module’s boost mode is
disabled. At this point, the converter load is powered by the stored
energy in the external capacitor. When the voltage on the external
capacitor falls to 20 VDC, the Capacitor Charged flag is released
(pulled low), indicating that 90% of the usable stored energy has
been depleted. If the connection has been made between the
Capacitor Charged pin and the converter’s Inhibit pin, the
converter will also be inhibited.
30 –
—
V
IN
= 22
V
IN
20 –
10 –
0–
—
V
IN
= 14
—
V
IN
= 10
V
IN
= 19
—
—
V
IN
= 23
V
IN
= 19
—
—
V
IN
= 12
40 –
30 –
VCS
WITH
DIODE
20 –
10 –
0–
VCS
CLOSED
—
V
CAP
—
V
CAP
V
IN
V
IN
VCS
CLOSED
RAMP
DOWN ON
EXT CAP
40 –
30 –
EXT
CAP
20 –
10 –
0–
V
CAP
= 35
—
—
V
CAP
= 40
V
CAP
= 20
—
POWER
FAIL
CAP
CHARGED
OPEN
0–
V
IN
= 10 – FLAGS ACTIVE
V
IN
= 14 – POWER FAIL FLAG
V
CAP
= 20 – CAP CHARGED FLAG
0–
V
IN
= 12 – POWER FAIL FLAG
V
CAP
= 35 – CAP CHARGED
{
INITIALIZATION &
CHARGING
NORMAL
LOW
OPERATION LINE
OPERATION
{
NORMAL
OPERATION
F
IGURE
5: HUMMER M
ODULE
S
IGNAL
D
IAGRAM
®
{
POWER FAIL
OPERATION
{
{
V= 10 – FLAGS NOT ACTIVE
V
IN
= 18 – VCS CLOSED
V
IN
= 18 – VCS CLOSES
V
IN
= 23 – VCS OPENS
V
IN
= 22–VCS OPENS
5
CRANE [ Crane Aerospace & Electronics. ]
