| 摘要 |
An integrated circuit device comprises an internal pull up current source (Ipup) and a pull up resistor (Rpup) connected in parallel between a voltage supply pin (Vs) and an output node (OUT). A standby switch (SBY) is connected in series with the pull up resistor (Rpup). The standby switch (SBY) is controlled by a standby detect means (SBY Detect), which is also connected to the output node (OUT). If it is desired to switch the device to standby mode, the output node (OUT) is externally drawn to ground by microprocessor (200). The circuit stays in the standby mode as long as the output node (OUT) is drawn to ground. In order to save current during standby mode, the standby detect means (SBY Detect) is operable to disconnect the pull-up resistance (Rpup) by means of standby switch (SBY). As the pull-up resistance (Rpup) is disconnected during the standby mode, the current source (Ipup) supplies a minimal current to the output node (OUT). This ensures that the circuit can always leave an undesired standby mode rapidly.
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