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VND05B / VND05B (011Y) / VND05B (012Y)

FUNCTIONAL DESCRIPTION

The device has a common diagnostic output for

both channels which indicates open load in on-

state, open load in off-state, overtemperature

From the falling edge of the input signal, the status

output, initially low to signal a fault condition

(overtemperature or open load on-state), will go

back to a high state with a different delay in case of

respectively.

This

feature

allows

to

discriminate the nature of the detected fault. To

protect

the

device

against

short-circuit

and

overcurrent condition, the thermal protection turns

the integrated PowerMOS off at a minimum

junction

temperature

of

When

this

automatically turned in again. In short-circuit the

protection reacts with virtually no delay, the sensor

(one for each channel) being located inside each

of the two PowerMOS areas. This positioning

allows the device to operate with one channel in

automatic thermal cycling and the other one on a

normal load. An internal function of the devices

ensures the fast demagnetization of inductive

function allows to greatly reduce the power

dissipation according to the formula:

where f= switching frequency and

The maximum inductance which causes the chip

temperature to reach the shutdown temperature in

a specified thermal environment is a function of

according to the above formula. In this device if the

16V, both channels will switch off.

PROTECTING

THE

DEVICE

AGAINST

REVERSE BATTERY

The simplest way to protect the device against a

continuous reverse battery voltage (-26V) is to

insert a Schottky diode between pin 2 (GND) and

ground, as shown in the typical application circuit

(fig. 2).

The consequences of the voltage drop across this

diode are as follows:

- If the input is pulled to power GND, a negative

respect to power GND).

- The undervoltage shutdown level is increased by

If there is no need for the control unit to handle

external analog signals referred to the power

GND, the best approach is to connect the

reference potential of the control unit to the device

ground (see application circuit in fig. 3), which

becomes the common signal GND for the whole

This solution allows the use of a standard diode.

Switching Time Waveforms