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L9904 데이터 시트보기 (PDF) - STMicroelectronics

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L9904
ST-Microelectronics
STMicroelectronics ST-Microelectronics
L9904 Datasheet PDF : 17 Pages
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L9904
3 FUNCTIONAL DESCRIPTION
3.1 General
The L9904 integrated circuit (IC) is designed to control four external N-channel MOS transistors in H-Bridge con-
figuration for DC-motor driving in automotive applications. It includes an ISO9141 compatible interface. A typical
application is shown in fig.9.
3.2 Voltage supply
The IC is supplied via an external reverse battery protection diode to the VVS pin. The typical operating voltage
range is down to 8V.
The supply current consumption of the IC composes of static and a dynamic part. The static current is typically
5.8mA. The dynamical current Idyn is depending of the PWM frequency fPWM and the required gate charge QGate
of the external power mos transistor. The current can be estimated by the expression:
Idyn = 2 · fPWM · QGate
An external power transistor with a gate charge of QGate = 160nC and a PWM frequency of fPWM = 20kHz re-
quires a dynamical supply current of Idyn = 6.4mA.
The total supply current consumption is IVS = 5.8mA + 6.4mA = 12.2mA.
3.3 Extended supply voltage range (ST)
The operating battery voltage range can be extended down to 6V using the additional components shown in
fig.7. A small inductor of L~150H (Ipeak~500mA) in series to the battery supply builts up a step up converter
with the switching open drain output ST. The switching frequency is typical 100kHz with a fixed duty cycle of
50%. The step up converter starts below VVS < 8V, increases the supply voltage at the VS pin and switches off
at VVS > 10V to avoid EME at nominal battery voltage. The diode D2 in series with the ST pin is necessary only
for systems with negative battery voltage. No additional load can be driven by the step up converter.
Figure 10.
VBAT
L1
D1
L9904
VS
C1
C2
D2
ST
-
+
= VSTH
fST
11/17

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