Rotation detection device

Patent metadata

Field	Value
Publication number	US-2020102001-A1
Application number	US-201916579351-A
Country	US
Kind code	A1
Filing date	Sep 23, 2019
Priority date	Sep 28, 2018
Publication date	Apr 2, 2020
Grant date	—

Abstract

A rotation detection device includes a rotation detection circuit, a step-up power supply circuit, a step-down power supply circuit, a first power supply path, and a second power supply path. The rotation detection circuit is configured to detect a rotation number of a motor that generates a torque applied to a steering mechanism of a vehicle, based on an electric signal. The electric signal is generated according to a rotation angle of the motor that is acquired through an in-vehicle sensor.

First claim

What is claimed is:

1 . A rotation detection device comprising:
a rotation detection circuit; a step-up power supply circuit; a step-down power supply circuit; a first power supply path; and a second power supply path, wherein the rotation detection circuit is configured to detect a rotation number of a motor that generates a torque applied to a steering mechanism of a vehicle, based on an electric signal, wherein the electric signal is generated according to a rotation angle of the motor that is acquired through an in-vehicle sensor, wherein the step-up power supply circuit is configured to perform a step-up operation so that a voltage of a DC power supply mounted in the vehicle is maintained at a normal level, when a vehicle power supply is turned on and the voltage of the DC power supply is lowered below the normal level, wherein the step-down power supply circuit is connected to the DC power supply and is configured to perform a step-down operation to a suitable voltage for operation of the rotation detection circuit, wherein the first power supply path connects the DC power supply and the step-down power supply circuit, wherein the second power supply path connects the step-up power supply circuit and the step-down power supply circuit, wherein power is supplied to the step-down power supply circuit via the first power supply path, when the vehicle power supply is turned on and the voltage of the DC power supply is maintained at the normal level, and wherein the power is supplied to the step-down power supply circuit via the second power supply path, when the vehicle power supply is turned on and the voltage of the DC power supply is lowered below the normal level.

2 . The rotation detection device according to claim 1 , further comprising:
a voltage detection circuit configured to detect the voltage of the DC power supply; a switch provided in the second power supply path and configured to open and close the second power supply path; and a switch control circuit configured to control opening and closing of the switch, wherein the switch control circuit maintains the switch in an open state, when the vehicle power supply is turned on and the voltage of the DC power supply detected through the voltage detection circuit is equal to or higher than a threshold voltage set based on an operable voltage of the step-down power supply circuit, and wherein the switch control circuit switches the switch from the open state to a closed state, when the vehicle power supply is turned on and the voltage of the DC power supply is lower than the threshold voltage.

3 . The rotation detection device according to claim 1 ,
wherein the first power supply path and the second power supply path are integrated at a step-down power supply circuit side, wherein the rotation detection device includes a first diode whose anode is provided on a DC power supply side and whose cathode is provided on the step-down power supply circuit side, in the first power supply path, and wherein the rotation detection device includes a second diode whose anode in provided on a step-up power supply circuit side and whose cathode is provided on the step-down power supply circuit side, in the second power supply path.

4 . The rotation detection device according to claim 1 ,
wherein the rotation detection device includes a first capacitor for instantaneous disconnection backup in the first power supply path and between the DC power supply and the step-down power supply circuit, and wherein the rotation detection device includes a second capacitor for instantaneous disconnection backup in the second power supply path and between the DC power supply and the step-up power supply circuit.

5 . The rotation detection device according to claim 1 ,
wherein the step-up power supply circuit is configured to stop operation when the vehicle power supply is turned off, and configured to operate so as to generate a constant voltage by switching the step-up operation and the step-down operation according to the voltage of the DC power supply when the vehicle power supply is turned on, wherein the rotation detection device includes another step-down power supply circuit configured to stop operation when the vehicle power supply is turned off, and configured to operate so as to lowered a voltage generated by the step-up power supply circuit to the suitable voltage for another power supply target except for the rotation detection circuit when the vehicle power supply is turned on, and wherein the voltage generated by the step-up power supply circuit is supplied to the other step-down power supply circuit through a third power supply path other than the first power supply path and the second power supply path when the vehicle power supply is turned on.

Assignees

• Jtekt Corp
• Renesas Electronics Corp

Inventors

• Kozuka Kenichi
• Oda Masato
• Kawahara Tadashi
• Oki Masashi

Classifications

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title

• B62D15/0235

  by measuring or deriving directly at the electric power steering motor · CPC title

• B62D15/021 Primary

  Determination of steering angle · CPC title

• B62D1/16

  Steering columns · CPC title

• B62D5/0409

  Electric motor acting on the steering column · CPC title