Direction indication lamp control device, direction indication device and wire disconnection detection method of the direction indication device

摘要

A direction indication lamp control device includes: a current control element including an end which outputs a drive current having a magnitude corresponding to amplitude of a pulse signal; a current clamp unit which limits the drive current to a current upper limit value; a voltage clamp unit which limits a reference voltage to a voltage upper limit value; and a wire disconnection detection unit which outputs a wire disconnection detection signal in a case where the drive current corresponding to the pulse wave of the pulse signal is equal to or less than a wire disconnection detection value, or in a case where the reference voltage is equal to the voltage upper limit value. The current upper limit value is smaller than the drive current flowing through a direction indication lamp when the reference voltage is the voltage upper limit value.

主权项

1. A direction indication lamp control device for controlling a direction indication lamp configured with LED elements connected in parallel, comprising:
a pulse signal generation unit that generates a pulse signal having a predetermined period; a current control element comprising one end to which power supply voltage is supplied, a control terminal to which the pulse signal is supplied, and the other end which outputs a drive current having a magnitude corresponding to amplitude of the pulse signal, the other end of the current control element being connected to one end of an external direction indication switch, and the other end of the direction indication switch being connected to the direction indication lamp; a current clamp unit which limits the drive current to a current upper limit value by decreasing amplitude of the pulse signal, in a case where the drive current exceeds the current upper limit value; a voltage clamp unit which limits a reference voltage of one end of the direction indication switch to a voltage upper limit value by decreasing the amplitude of the pulse signal, in a case where the reference voltage exceeds the voltage upper limit value; and a wire disconnection detection unit which outputs a wire disconnection detection signal in a case where the drive current corresponding to the pulse wave of the pulse signal is equal to or less than a wire disconnection detection value which is less than the current upper limit value, or in a case where the reference voltage is equal to the voltage upper limit value, wherein the current upper limit value is smaller than the drive current flowing through the direction indication lamp when the reference voltage is the voltage upper limit value.