5.1.6 Low-Current Bus Monitor, Standby and Sleep Modes

Many applications are looking to lower-power opportunities as more electronics are added to designs. The standby mode in many TI transceivers is generally referred to as the “listen only” mode, because in standby, the driver circuitry is switched off while the receiver continues to monitor bus activity. In the occurrence of a dominant bit on the bus, the receiver passes this information along to its DSP/CAN controller which in turn activates the circuits that are in standby. This is achieved by placing a logic-low level on the Rs pin (pin 8) of the device.

The difference between the standby mode and the sleep mode is that both driver and receiver circuits can be switched off to create an extremely low-power sleep mode with no bus monitor. The local controller actively places the device into and out of sleep mode.

The HVD1040 contains the best of both standby and sleep features with a low-power (5 μA typical) bus monitor. The device driver and receiver circuitry is switched off while a small comparator monitors the bus and toggles the receiver output on bus activity.