L9386 Просмотр технического описания (PDF) - STMicroelectronics

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производитель

L9386

Dual intelligent power low side switch

STMicroelectronics 

Electrical specifications

L9386

2.4

Circuit description

The L9386 is a dual low side driver for inductive loads like valves in automotive environment.

The device is enabled by a common CMOS compatible ENABLE high signal. The internal

pull down current sources at the ENABLE and INPUT pins protect the device in open input

conditions against malfunctions. An output slope limitation for du/dt is implemented to

reduce the EMI. An integrated active flyback voltage limitation clamps the output voltage

during the flyback phase to 50V.

Each driver is protected against short circuit and thermal overload. In short circuit condition

the output will be disabled after a short delay time tDOL to suppress spikes. This disable is

latched until a negative slope occur at the correspondent input pin. The thermal disable for

TJ > 175 °C of the output will be resetted if the junction temperature decreases about 20 °C

below the disable threshold temperature.

For the real time error diagnosis the voltage and the current of the outputs are compared

with internal fixed values VOUV for OFF and IOUC for ON conditions to recognize open load

(RL ≥ 20 kΩ, RL > 38Ω) in ON and OFF conditions. The diagnostic operates also in the

extended supply voltage range of 4.5 V ≤ VS ≤ 32 V.

Also the output voltages VO1,2 are compared against each other in OFF condition with a

fixed offset of ΔVOUV 1,2 to recognize GND bypasses. To suppress mail ΔVO diagnoses

during the flyback phases of the compared output, the ΔVO diagnostic

includes a latch function. Reaching the flyback clamping voltage VOC the diagnostic signal

is resetted by a latch. To activate again this kind of diagnostic a low signal at the

correspondent INPUT or the ENABLE pin must occur (see also Figure 5).

The diagnostic output level in connection with different ENABLE and INPUT conditions

allows to recognize different fail states, like overtemperature, short to VSS, short to GND,

bypass to GND and disconnected load (see also Table 5 on page 6).

The diagnostic output is also protected against short to UDmax. Oversteping the over load

current threshold IOo, the output current will be limited internally during the diagnostic

overload delay switch-off time tDOL.

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