Relay drive circuit with a current mirror circuit

Patent metadata

Field	Value
Publication number	US-10593499-B2
Application number	US-201715657124-A
Country	US
Kind code	B2
Filing date	Jul 22, 2017
Priority date	Aug 4, 2016
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

The present invention is intended to provide constant drive conditions of a relay switch. A relay drive circuit includes a current mirror circuit, a current suppression circuit 26, and a transistor Q3. The current mirror circuit includes a transistor Q1, a first resistor element R1, a transistor Q2, and a second resistor element R2. A relay coil 18 is provided on a current supply path extending from a collector terminal of the transistor Q1 to an earth conductor. The current suppression circuit 26 includes a capacitor C1 as a current suppression element configured to suppress, after conduction between an emitter terminal and a collector terminal of the transistor Q2 has been made, the current flowing through the current suppression element itself as compared to that in such conduction.

First claim

What is claimed is:

1. A relay drive circuit comprising:
a current mirror circuit including a first semiconductor element and a second semiconductor element, the current mirror circuit being configured to adjust a current flowing through a first current path including the first semiconductor element according to a current flowing through a second current path including the second semiconductor element;
a control switch provided on the second current path, and
a current suppression circuit provided on the second current path and configured to suppress, after conduction of the second semiconductor element has been made, the current flowing through the second current path as compared to that in the conduction of the second semiconductor element,
wherein the current suppression circuit includes
a current suppression element configured to suppress, after the conduction of the second semiconductor element has been made, a current flowing through the current suppression element itself as compared to that in the conduction of the second semiconductor element, and
a current determination element configured to divide the current flowing through the current suppression element and to determine the current flowing through the second current path,

wherein a relay coil is provided on the first current path.

2. The relay drive circuit according to claim 1 , wherein
the current mirror circuit includes
a first resistor element provided at a section of the first current path from a DC power supply to the first semiconductor element, and
a second resistor element provided at a section of the second current path from the DC power supply to the second semiconductor element.

3. The relay drive circuit according to claim 2 , wherein
a resistance value of the second resistor element is greater than a resistance value of the first resistor element.

4. A relay drive circuit comprising:
a current mirror circuit including a first semiconductor element and a second semiconductor element, the current mirror circuit being configured to adjust a current flowing through a first current path including the first semiconductor element according to a current flowing through a second current path including the second semiconductor element;
a control switch provided on the second current path, and
a current suppression circuit provided on the second current path and configured to suppress, after conduction of the second semiconductor element has been made, the current flowing through the second current path as compared to that in the conduction of the second semiconductor element,
wherein the current suppression circuit includes
a capacitor and
a current determination element configured to divide a current flow for the capacitor and to determine the current flowing through the second current path,

wherein a relay coil is provided on the first current path.

5. The relay drive circuit according to claim 4 , wherein
the current suppression circuit includes
a resistor element connected in series with the capacitor, and

the current determination element is connected in parallel such that a current flow is divided for the capacitor and the resistor element connected in series.

6. The relay drive circuit according to claim 4 , wherein
the current mirror circuit includes
a first resistor element provided at a section of the first current path from a DC power supply to the first semiconductor element, and
a second resistor element provided at a section of the second current path from the DC power supply to the second semiconductor element.

7. The relay drive circuit according to claim 6 , wherein
a resistance value of the second resistor element is greater than a resistance value of the first resistor element.

Assignees

• Onkyo Kk

Inventors

• Murai Naofumi

Classifications

• H01H47/32

  Energising current supplied by semiconductor device · CPC title

• H01H2047/025

  with taking into account of the thermal influences, e.g. change in resistivity of the coil or being adapted to high temperatures · CPC title

• H01H47/325 Primary

  by switching regulator · CPC title

• H01H47/02 Primary

  for modifying the operation of the relay · CPC title