Claims
- 1. A load driving apparatus comprising:a first switching element which is connected to a first power source supplying a first voltage and connected to a load; a second switching element which is connected to a second power source supplying a second voltage lower than the first voltage and connected to the load; current detecting means which detects a value of current flowing in the load; and control means which is connected the first switching element, the second switching element, and the current detecting means to control a voltage to be supplied to the load, wherein the control means turns the second switching element into ON state at first, continues to supply the second voltage from the second power source to the load while the value of current detected by the current detecting means is more than a predetermined value, and turns the second switching element in OFF state and drives the first switching element to supply the first voltage from the first power source to the load once the value of current detected by the current detecting means becomes below the predetermined value.
- 2. A load driving apparatus according to claim 1, further comprising direct current voltage converting means which is connected to the first power source and which lowers the first voltage.
- 3. A load driving apparatus according to claim 1, wherein the first voltage from the first power source is converted to a pulse voltage by means of the direct current voltage converting means having PWM (Pulse Width Modulation) control and is supplied to the load.
- 4. A load driving apparatus according to claim 1, wherein the current detecting means detects a value of current flowing in a resistor provided between the second switching element and the load.
- 5. A load driving apparatus according to claim 1, wherein the load is a lamp.
- 6. A load driving apparatus according to claim 1, wherein the predetermined value is set to a value indicating that the load has become a steady state.
Priority Claims (1)
Number |
Date |
Country |
Kind |
P 2001-239524 |
Aug 2001 |
JP |
|
CROSS REFERENCE TO RELATED APPLICATION
This application claims benefit of priority under 35 U.S.C. §119 to Japanese Patent Application No.2001-239524, filed on Aug. 7, 2001, the entire contents of which are incorporated by reference herein.
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