L9380 查看數據表（PDF） - STMicroelectronics

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L9380

Triple high-side MOSFET driver

STMicroelectronics 

L9380

4

Functional description

Functional description

The triple high-side Power-MOS Driver features all necessary control and protection

functions to switch on three Power-MOS transistors operating as High-Side switches in

automotive electronic control units. The key application field is relays replacement in

systems where high current loads, usually motors with nominal currents of about 40 A

connected to ground, has to be switched.

A high signal at the EN pin enables all three channels. With enable low gates are clamped to

ground. In this condition the gate sink current is higher than the specified 3 mA. An enable

low signal makes also a reset of the timer.

A low signal at the inputs switch on the gates of the external MOS. A short circuit at the input

leads to permanent activation of the concerned channel. In this case the device can be

disabled with the enable pin. The charge pump loading is not influenced due to the enable

input.

An external N-channel MOS driver in high side configuration needs a gate driving voltage

higher than VS. It is generated by means of a charge pump with integrated charge transfer

capacitors and one external charge storage capacitor CCP.

The charge pump is dimensioned to load a capacitor CCP of 33 nF in less than 20 ms up to

8V above VS. The value of CCP depends on the input capacitance of the external MOS and

the decay of the charge pump voltage down to that value where no significant influence on

the application occurs.

The necessary charging time for CCP has to be respected in the sequence of the input

control signals.

As a consequence the lower gate to source voltage can cause a higher drop across the

Power-MOS and get into overload condition. In this case the overload protection timer will

start.

After the protection time the concerned channel will be switched off. Channel 3 is not

equipped with an overload protection. The same situation can occur due to a discharge of

the storage capacitor caused by the gate short to ground. The gate driver that is supplied

from the pin CP, which is the charge pump output, has a sink and source current capability

of 3 mA. For a short-circuit of the load (source to ground) the L9380 has no gate to source

limitation. The gate source protection must be done externally.

Channel 1 and 2 provide drain to source voltage sensing possibility with programmable

shut-off delay when the activation threshold was exceeded.

This threshold VDSmin is set by the external resistor RD. The bias current flowing through this

resistor is determined by the programming resistor RPR. This external resistor RPR defines

also the charge and discharge current of the timer capacitor CCT. The drain to source

threshold VDSmin and the timer shut off delay time Toff can be calculated:

VDSmin

=

VP

R







R--R---P--D--R--

Toff = 4.4 CT RPR

Doc ID 5853 Rev 4

9/18

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