L9803 STMicroelectronics, L9803 Datasheet - Page 93

• Manufacturer Part Number: L9803
• Description: Super Smart Power Motor Driver With 8-bit Mcu, Ram, Eeprom, Adc, Wdg, Timers, Pwm And H-bridge Driver
• Manufacturer: STMicroelectronics

L9803
5.7.3
5.7.4
5.8
5.8.1
Functional Description
The Can Bus Transceiver is used as an interface between a CAN controller and the physical
bus. The device provides transmitting capability to the CAN controller. The transceiver has
one logic input pin (TX), one logic output pin (RX) and two Input/Output pins for the electrical
connections to the two bus wires (CAN_L and CAN_H). The microcontroller sends data to
the TX pin and it receives data from the RX pin. The transmission slew-rates of CAN_H and
CAN_L voltage are controlled to reduce RFI and EMI. The transceiver is protected against
short circuit or overcurrent: If I
CAN_H and CAN_L power transistors are switched off and the transmission is disabled for
T
CAN Transceiver Disabling function
The transceiver can be disabled and forced to move in a low power consumption mode,
setting CANDS bit in DCSR register. When the transceiver is in this mode it can not receive
nor transmit any information to the bus. The only way to have again on board the CAN
capabilities is reset CANDS bit. The CAN protocol handler can not disable nor enable the
transceiver and there is no way to communicate to the controller the transceiver is down.
The disabling function has the only purpose to allow the reduction of the current
consumption of the device in application not using the CAN at all or using it for particular
functions (such like debugging). Current consumption reduction, when disabling the
trasceiver, can be as high as 15mA.
Note When the CAN capabilities of L9803 are not needed additional consumption reduction
can be achieved putting the CAN controller in Stand-by Mode.
Figure 44. Can Bus Transceiver Block Diagram
Power Bridge
Introduction
The power part of the device consists of two identical independent DMOS half bridges. It is
suited to drive resistive and inductive loads.
D
=25µs typical.
ŠŠ
RX0
TX0
CANH
−
+
and/or I
R
R
R
R
CANL
2R
2R
exceeds a current thresholds I
OVERCURRENT
OVERCURRENT
DETECTION
DETECTION
CONTROL
POWER
VDD
On-Chip Peripherals
GND
CAN_H
CAN_L
SC
, then the
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