zxct1032 Zetex Semiconductors plc., zxct1032 Datasheet - Page 7

• Manufacturer Part Number: zxct1032
• Description: Zxct1032 - High-side Inrush And Current Limit Controller
• Manufacturer: Zetex Semiconductors plc.

2 The output voltage also increases due to the load current powering up the load and charging
3 Fuse operation is provided by the trip comparator whose threshold voltage is set by V
Issue 4 - June 2007
© Zetex Semiconductors plc 2007
any capacitance. After the initial soft start (load current stabilizing) the timing capacitor
charges up to 4V and the device enters its normal mode of operation. The external MOSFET
will be now fully enhanced minimizing any serial voltage drop.
The ZXCT1032 has now entered its over-current detector mode; it is effectively “transparent”
to the load until the current monitor output exceeds the trip point.
(internally nominally 2.1V, although this threshold can easily be overdriven). As the load
current increases, so does the monitor voltage. When the current monitor output voltage
exceeds V
results:
a The output drive is disabled.
b The open collector Flag output goes low to indicate a fault condition.
c The 200 A current source is turned off and C
source.
ISET
2.5
1.5
0.5
2
1
0
20
18
16
14
12
10
0
8
6
4
2
0
, the trip comparator output goes high and sets the latch with the following
0
I
LOAD
ZXCT1032 Timing in over-current condition
V
LOAD
5
ZXCT1032 Normal Operation
I
LOAD
5
0
V
V
V
ISET
ISET
CT
Time ms
Time (ms)
10
7
10*V
T
starts to discharge slowly via a 3.3 A current
SENSE
V
V
R
I
C
V
Trip current = 1 A
LOAD
IN+
SENSE
T
ISET
CT
1
0
0
= 2.1 V
15
= 18 V
= 0.2
= 220 nF
> 1 A
V
R
C
V
Trip current = 1A
IN+
SENSE
T
ISET
= 220nF
= 18V
= 2.1V
= 0.2Ω
20
1
0.8
0.6
0.4
0.2
0
ZXCT1032
1
5
0
www.zetex.com
2.5
2
1.5
1
0.5
0
ISET