L9524C-TR Просмотр технического описания (PDF) - STMicroelectronics

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L9524C-TR

Glow plug system control IC

STMicroelectronics 

Functional description

L9524C

4.3

Control input

The control input (CI) pin is resistively pulled up RCI to the supply voltage VVS such that

VCI=VCI off and the glow plugs are switched off by default. The L9524C is controlled by

transitions of VCI from VCI off to VCI on (falling edge) and vice versa (rising edge). Voltage

level changes of VCI which last shorter than tCI fil are ignored.

In transistor mode (modes 3 to 6) the L9524C expects a PWM signal at the CI pin. Each

falling edge starts measuring its on time tCI on (time until next rising edge, i.e. length of this

low pulse) and its period TCI (time until next falling edge). The end of a pulse group is

detected if no falling edge occurs for a time greater than tCI to and the glow plugs are

switched off. Therefore, it is not possible to switch on the glow plugs permanently with one

exception: if the low voltage level of the first falling edge is greater than VCI to the glow plugs

remain switched on as long as this low pulse lasts.

Figure 4. Control input signal in transistor mode (modes 3 to 6)

VCI

tCI to

TCI

VCI off

0.6 . VVS

0.4 . VVS

tCI fil

ignored

tCI fil

(shorter than tCI fil)

VCI on

tCI on

glow plug

tCI to

tCI to

t

1

ON

tCI fil +t del

tCI fil +t del

OFF

t

Figure 5. Permanent switch on of glow plugs at first falling edge in transistor mode

(modes 3 to 6)

VCI

VCI off

0.6 . VVS

0.4 . VVS

VCI on

VCI to

tCI to

glow plug

tCI to

1

ON

OFF

tCI to

tCI to

t

t

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