Datasheet

MAX5934/MAX5934A
Positive High-Voltage, Hot-Swap Controllers with
Selectable Fault Management and Status Polarity
12 ______________________________________________________________________________________
Undervoltage and Overvoltage Detection
An undervoltage fault is detected when V
ON
goes
below the trip point (V
ONL
= 1.233V). When this occurs,
GATE pulls low and stays low until V
ON
rises above
(V
ONH
= 1.313V).
An example of overvoltage protection is shown in
Figure 8. Zener diode D1 turns on when V
IN
exceeds
the diode’s breakdown voltage and begins to pull
TIMER high. When V
TIMER
goes higher than 1.233V, a
fault is detected and GATE pulls low. As a result, Q1
turns off. Figure 9 shows overvoltage waveforms for V
IN
(see the Fault Management ( LATCH /RETRY) section for
restart conditions).
Supply Transient Protection
The MAX5934/MAX5934A are guaranteed to be safe
from damage with supply voltages of up to 85V. Spikes
at voltages above 85V may damage the part.
Instantaneous short-circuit conditions, can cause large
RESPONSE TIME TO OVERCURRENT
V
CC
- V
SENSE
(mV)
PROPAGATION DELAY (µs)
200100
2
4
6
8
10
12
14
0
0 300
50
150
250
Figure 7. Response Time to Overcurrent
MAX5934
MAX5934A
ON
C
L
OUT
GATESENSE
V
CC
16 14 11
9
4
6
5
7
12
8
M1
R1
1kΩ
5%
R
SENSE
0.025Ω
C1
10nF
R4
59kΩ
1%
R6
24kΩ
5%
R7
24kΩ
5%
R8
24kΩ
5%
R10
1kΩ
1%
R9
90kΩ
1%
V
IN
R
G
10Ω
5%
C
TIMER
0.68µF
R5
3.57kΩ
1%
FB1
2
10
1
3
15
PWRGD1
PWRGD2
TIMER
LATCH/RETRY
V
CC
FB2
PWRGD3
V
MONITOR
PWRGD
DC
GND
V
CC
POL_SEL
V
CC
IRF530
D1
30V
1N5256B
R2
49.9kΩ
1%
R3
3.4kΩ
1%
Figure 8. Overvoltage Detection