9-24

HIP1090

Applications

The HIP1090 may be used as a “hard-wired pass-thru”

device to protect the load from source voltage transients or

may be used as an active high side power interface switch

with up to 1A of Load current capability. An ON state

range required to activate the high pass switch, allowing the

supply source to conduct through the PNP to the load. When

open (no conduction). Figure 2 shows an HIP1090

comparison to the hard wired circuit of Figure 1 where pin 2

is fixed at ground, pin 2 in the circuit of Figure 2 is switched

from open to ground to turn-ON the high pass switch. Used

in this mode, the HIP1090 is both an effective transient

terminal may be active or passive and conducts typically

less than 50mA of current. The HIP1090 used in the con-

trolled switching mode retains all of the protected features of

the device. In either circuit the output capacitor may be

increased in size to hold charge longer during transient

interruptions at the input. The charge duration for larger

capacitors or for lamp loads is tolerated because of the

internal short circuit current limiting protection. Sustained

short circuits may cause the junction temperature to reach

FIGURE 1. TYPICAL APPLICATION OF THE HIP1090 AS A TRANSIENT SUPPRESSOR IN A “PASS-THRU” MODE

FIGURE 2. TYPICAL APPLICATIONS OF THE HIP1090 AS A TRANSIENT SUPPRESSOR IN A HIGH PASS SWITCH MODE

BASE

CURRENT

LIMIT

2

(CONTROL OR GND)

3

CURRENT

AMPLIFIER

OVER-

VOLTAGE

SHUTDOWN

DETECTOR

THERMAL

LIMIT

1

SWITCH

INPUT

0.47

µF

DASH PANEL LOAD

TO OTHER

LIGHTS

AND

INSTRUMENTS

BASE

CURRENT

LIMIT

2

(CONTROL)

3

CURRENT

AMPLIFIER

OVER-

VOLTAGE

SHUTDOWN

DETECTOR

THERMAL

LIMIT

1

INPUT

0.47

µF

SWITCH

OFF

TO

1000

µF

NOTE:

ON