L6230

Circuit description

Doc ID 18094 Rev 2

13/24

5.3

Non-dissipative overcurrent detection and protection

The L6230 integrates an overcurrent detection circuit (OCD) for full protection. This circuit

provides output-to-output and output-to-ground short circuit protection as well. With this

internal over current detection, the external current sense resistor normally used and its

associated power dissipation are eliminated. Figure 10 shows a simplified schematic for the

overcurrent detection circuit.

To implement the over current detection, a sensing element that delivers a small but precise

fraction of the output current is implemented with each high side power MOS. Since this

current is a small fraction of the output current there is very little additional power

comparator signals a fault condition. When a fault condition is detected, an internal open

drain MOS with a pull down capability of 4 mA connected to pin DIAG is turned on.

The pin DIAG-EN can be used to signal the fault condition to a

μC and to shut down the

Figure 10.

Overcurrent protection simplified schematic

recovering normal operation can be easily programmed by means of the accurate

Figure 13

time.

disable time.

+

OVER TEMPERATURE

HIGH SIDE DMOS

POWER SENSE

1 cell

POWER SENSE

1 cell

POWER SENSE

1 cell

POWER DMOS

n cells

POWER DMOS

n cells

POWER DMOS

n cells

HIGH SIDE DMOS

HIGH SIDE DMOS

OCD

COMPARATOR

TO GATE

LOGIC

INTERNAL

OPEN-DRAIN

40

Ω TYP.

DIAG\EN

μC or LOGIC

D02IN1381