ELECTRIC POWER SUPPLY DEVICE

• US 20100127677A1
• Filed: 03/18/2009
• Published: 05/27/2010
• Est. Priority Date: 03/19/2008
• Status: Active Grant

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Ohshima, Shunzou
• Granted Patent: US 8,143,867 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: B60Q 11/00 Arrangement of monitoring devices for devices provided for in groups B60Q1/00 - B60Q9/00
• CPC Class Codes: H02H 3/087 for dc applications
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches
• CPC Class Codes: H03K 17/302 in field-effect transistor switches
• CPC Class Codes: H05B 39/04 Controlling

Abstract

In an electric supply device of the present invention, since a semiconductor element T1 is interrupted before a drain voltage V1 of the semiconductor element T1 is lower than an in-phase input minimum voltage, a load circuit can be assuredly protected. Further, assuming that a first decided voltage is L-V1 and a second decided voltage V3, when the voltage V1 becomes “V1<L-V1”, a retry operation is carried out. When the number of times of “V1<L-V1” reaches N1 times, or when the number of times of “L-V1<V1<V3” reaches N2 times, an interrupted state of the semiconductor element T1 is held to protect the load circuit. Further, when the voltage V1 suddenly drops due to an imperfect contact of a connector 11, a minimum value of the voltage V1 is not a stable value and the interrupted state of the semiconductor T1 is not held.

Claims

1. An electric power supply device comprising:

a semiconductor element;

a power source having a positive terminal to which a first main electrode of the semiconductor element is connected through a wiring of a power source side;

a load connected between a second main electrode of the semiconductor element and a ground; and

a control portion that controls the semiconductor to be turned on and off to supply an electric power to the load,

wherein when a first voltage of a point between the first main electrode and the wiring of the power source side is lower than a first decided voltage, the control portion controls the semiconductor element to be turned off, and the control portion controls the semiconductor element to be turned on when a first prescribed time is elapsed after the semiconductor element is turned off; and

wherein when the semiconductor element is turned on after the first prescribed time is elapsed so that a minimum value of the first voltage exceeds the first decided voltage, the control portion controls the semiconductor element to continue a turning on state, and when the first voltage is lower than the first decided voltage, the control portion controls the semiconductor element to hold a turning off state.

3. The electric power supply device according to claim 1, wherein when the first voltage is lower than the first decided voltage, the control portion controls the semiconductor element to be turned off, then, when the semiconductor element is turned on after the first prescribed time is elapsed, if the first voltage is lower than the first decided voltage again, the control portion controls the semiconductor element to be turned off again, and then, when the control portion repeats an operation for turning on the semiconductor element again after the first prescribed time is elapsed a first prescribed number of times so that the first voltage obtained when the semiconductor element is turned on during all tries is lower than the first decided voltage, the control portion controls the semiconductor element to hold the turning off state.

4. The electric power supply device according to claim 3, wherein the control portion sets a second decided voltage higher than the first decided voltage, then, when the first voltage is lower than the first decided voltage, the control portion controls the semiconductor element in a turning on state to be turned off, then, when the semiconductor element is turned on again after the first prescribed time is elapsed, if the minimum value of the first voltage is higher than the first decided voltage and is lower than the second decided voltage, the control portion controls the semiconductor element to be repeatedly turned on and off at intervals of a second prescribed time, then, when the first voltage is lower than the first decided voltage during a repeating time, the control portion controls the semiconductor element to be repeatedly turned on and off at intervals of the first prescribed time, and during a process of the repeated control, when the semiconductor element is turned on, if the minimum voltage of the first voltage is repeatedly higher than the first decided voltage and is lower than the second decided voltage continuously a second number of times, or if the minimum value of the first voltage is repeatedly lower than the first decided voltage continuously the first number of times, the control portion controls the semiconductor element to hold an interrupted state.

5. The electric power supply device according to claim 4, wherein when the semiconductor element is turned on again after the semiconductor element is turned off, if the minimum value of the first voltage is higher than the first decided voltage and is lower than the second decided voltage, the control portion raises the second decided voltage and then controls the semiconductor element to be turned on.

6. The electric power supply device according to claim 3, wherein the first prescribed time is changed at random.

7. The electric power supply device according to claim 4, wherein the first prescribed time and the second prescribed time are changed at random.

2. An electric power supply device comprising:

a plurality of load circuits, each of which having a semiconductor element and a load connected in series, wherein first main electrodes of the plurality of semiconductor elements are respectively connected together through a first connecting point,

a power source having a positive terminal to which the first connecting point is connected only through a wiring of a power source side, wherein second main electrodes of the plurality of semiconductor elements are respectively connected to the loads corresponding thereto; and

a plurality of control portions that respectively control the semiconductor elements corresponding to the load circuits to be turned on and off to supply an electric power to the corresponding load circuits,

wherein when a first voltage of the first connecting point is lower than a first decided voltage, the control portions control all the semiconductor elements in turning on states to be turned off, and the control portions control the semiconductor element that are turned off to be sequentially turned on with a prescribed time difference when a first prescribed time is elapsed after the semiconductor elements are turned off; and

wherein when the semiconductor elements are turned on after the first prescribed time is elapsed so that a minimum value of the first voltage exceeds the first decided voltage, the control portions control the semiconductor elements to continue turning on states, and when the first voltage is lower than the first decided voltage, the control portions control the semiconductor elements to respectively hold turning off states.

8. The electric power supply device according to claim 2, wherein when the first voltage is lower than the first decided voltage, the control portion controls all the semiconductor elements in turning on states to be turned off, then, when the semiconductor elements that are turned off are sequentially and respectively turned on after the first prescribed time is elapsed, if the first voltage is lower than the first decided voltage again, the control portion controls the semiconductor elements in turning on states to be turned off again, and then, when the control portion repeats an operation for turning on one of the semiconductor elements again after the first prescribed time is elapsed a first prescribed number of times so that the first voltage obtained when the relevant semiconductor element is turned on is lower than the first decided voltage during all tries, the control portion controls the relevant semiconductor element to hold the turning off state.

9. The electric power supply device according to claim 8, wherein the control portion sets a second decided voltage higher than the first decided voltage, then, when the first voltage is lower than the first decided voltage, the control portion controls the semiconductor elements in a turning on state to be turned off, then, when one of the semiconductor elements is turned on again after the first prescribed time is elapsed, if the minimum value of the first voltage is higher than the first decided voltage and is lower than the second decided voltage, the control portion controls the relevant semiconductor element to be repeatedly turned on and off at intervals of a second prescribed time, then, when the first voltage is lower than the first decided voltage during a repeating time, the control portion controls the relevant semiconductor element to be repeatedly turned on and off at intervals of the first prescribed time, and during a process of the repeated control, when the relevant semiconductor element is turned on, if the minimum voltage of the first voltage is repeatedly higher than the first decided voltage and is lower than the second decided voltage continuously a second number of times, or if the minimum value of the first voltage is repeatedly lower than the first decided voltage continuously the first number of times, the control portion controls the relevant semiconductor element to hold an interrupted state.

10. The electric power supply device according to claim 9, wherein when the semiconductor elements are sequentially turned on again after the semiconductor elements are turned off, if the minimum value of the first voltage is higher than the first decided voltage and is lower than the second decided voltage, the control portion raises the second decided voltage and then controls the semiconductor elements to be turned on.

11. The electric power supply device according to claim 8, wherein the first prescribed time is changed at random.

12. The electric power supply device according to claim 9, wherein the first prescribed time and the second prescribed time are changed at random.