Control device with time measuring function
View Patent ↗A control device with a time measuring function measures a turned-off time of an ignition switch with a low consumption current and high accuracy at a level adapted for a demand from the controlling side, as well as a turned-on time of the ignition switch. The control device also measures an accumulative turned-on time of the ignition switch. The control device comprises a battery, a microcomputer for computing a control variable to control a control target, a time measuring unit, a clock source for the microcomputer, a clock source for the time measuring unit, and a unit for changing over operation of the time measuring unit depending on an intended use. The time measuring unit operates regardless of run/stop of the microcomputer.
1. A control device with a time measuring function utilized for a vehicle, said control device comprising:
a microcomputer for computing a control variable to control a vehicle component;
a timer for measuring time;
a clock source for said microcomputer; and
a separate clock source for said timer being independent of said clock source for said microcomputer,
wherein said timer regardless of run/stop of said microcomputer, and
said microcomputer and said timer are configured to be electrically supplied from an onboard battery of the vehicle.
2. A control device with a time measuring function according to claim 1 , wherein operation of said timer time is controlled by a power supply switch for controlling turning-on/off of said control device.
3. A control device with a time measuring function according to claim 2 , wherein said timer selectively measures a turned-on period or a turned-off period of said power supply switch in accordance with a control signal from said microcomputer.
4. A control device with a time measuring function according to claim 2 , wherein said timer measures a turned-on period of said power supply switch.
5. A control device with a time measuring function according to claim 4 , further comprising an electrically rewritable nonvolatile memory and means for storing the turned-on period of said electrical supply from said onboard battery.
6. A control device with a time measuring function according to claim 2 , wherein said timer measures a turned-off period of said power supply switch.
7. A control device with a time measuring function according to claim 1 , wherein the clock source for said microcomputer and the clock source for said timer are individually provided independently of each other.
8. A control device with a time measuring function according to claim 1 , wherein said timer includes a counter for measuring time, and said control device further comprises means for holding a counter value and means for stopping the clock source for said timer, when the counter value of said timer overflows during measurement of the turned-off period of said control device.
9. A control device with a time measuring function according to claim 8 , further comprising means for starting count-up of the counter value from a value other than 0 when a counter of said timer is started up.
10. A control device with a time measuring function according to claim 9 , wherein said control device further comprises means for starting count-up of the counter value from 1 when the counter of said timer is started up.
11. A control device with a time measuring function according to claim 9 , further comprising means for detecting whether said onboard battery is connected or disconnected, and means for clearing the counter value of said timer to 0 when said onboard battery is connected again from a disconnected state.
12. A control device with a time measuring function according to claim 9 , further comprising means for controlling operation of the counter of said timer from said microcomputer.