Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Yasuhiko Harada

Mitsuru Aoki

Satoshi Shizuka

Shizuo Manabe

Kenta Imamiya

A bipolar stepper motor driving device drives a stepper motor including stator coils having plural phases. The bipolar stepper motor driving device includes H-bridge circuits, a current detector, a control circuit, and a re-turning-on instruction unit. The H-bridge circuits are provided correspondingly to the phases of the respective stator coils. The current detector detects current flowing in the stator coils. The control circuit executes drive control of the H-bridge circuits. The re-turning-on instruction unit commands the control circuit to switch into a short-circuited state a stator coil which has shifted from an energized state to an off-state among the stator coils, on a condition that an absolute value of a reverse current detected by the current detector has changed from a value larger than a threshold current value to a value smaller than the threshold current value.

Bipolar stepper motor driving device

In an inductive load control device, an energization controller controls an operation of an H-bridge circuit to switch from an energized state to a regenerative state when a load current value is equal to or greater than a first threshold value at a time after a mask time has elapsed from a start time of a reference cycle, and a short-circuit determination processor determines whether the short-circuit abnormality has occurred based on whether the load current value is equal to or greater than a second threshold value greater than the first threshold value. The short-circuit determination processor further determines whether the short-circuit abnormality has occurred based on the regenerative current value in the regenerative state when the load current value does not reach the second threshold value within the mask time.

Inductive load control device

A load driving apparatus supplies an electric power to a load via a full-bridge circuit. The load driving apparatus detects a load current by a current sensing resistor. A controller in the load driving apparatus generates a drive signal by switching between a first reference circuit outputting a first reference signal with a first reference cycle and a second reference signal outputting a second reference signal with a second reference cycle. A calculator in the load driving apparatus is used to supply a drive signal to the full-bridge circuit for supplying power to the load. When the controllerdetects that the value of the load current is not reaching predetermined current threshold values, within either of the first reference cycle or the second reference cycle due to temperature fluctuations, the controller switches to either the first reference circuit or the second reference circuit to stabilize the value of the load current around an average value.

Load driving apparatus

An electronic control unit mounted in an object includes: a rewritable memory of control and reprogramming software; a not-always-on power supply system micro-computer operating in control and reprogramming modes and connected/disconnected with a power source; and an always-on power supply system micro-computer operating in the control and reprogramming modes and constantly connected with the power source. Each micro-computer includes: a first mode determination device determining whether to operate in an on-board mode when the power source starts to supply the electric power; and a second mode determination device determining whether to operate in the reprogramming mode. The always-on power supply system micro-computer includes a first transition device that detects a change in a power supply state of the not-always-on power supply system micro-computer. The first transition device switches a processing to a determination executed by the first mode determination device when the power supply state has changed.

Growing community of inventors

Kariya, Japan

Yasuhiko Harada