초록 ▼

By switching the NMOS (11) on and off, a drive current passes through a solenoid (15). The drive current passes through a conversion circuit (16), and an amplifier circuit (17) outputs a current detection result by amplifying the output voltage of the conversion circuit (16). Because a plurality of

By switching the NMOS (11) on and off, a drive current passes through a solenoid (15). The drive current passes through a conversion circuit (16), and an amplifier circuit (17) outputs a current detection result by amplifying the output voltage of the conversion circuit (16). Because a plurality of resistor elements (161 to 16n) that constitute the conversion circuit (16), together with elements that constitute the amplifier circuit (17) are formed diffused to a semiconductor substrate (100), even if the attribute changes by the conversion circuit (16) generating heat, by the drive current, the amplifier circuit (17) becomes approximately the same temperature, and the attribute changes. Therefore, a highly accurate current detection becomes possible without using components for temperature correction.

대표청구항 ▼

The invention claimed is: 1. A current detection circuit comprising: a conversion circuit (16) configured to allow a current to flow therethrough to a power load, and generate an electronic signal passing therethrough; corresponding to the current passing therethrough; and an amplifier circuit (17)

The invention claimed is: 1. A current detection circuit comprising: a conversion circuit (16) configured to allow a current to flow therethrough to a power load, and generate an electronic signal passing therethrough; corresponding to the current passing therethrough; and an amplifier circuit (17)configured to include a resistor circuit (21 to 23) for gain setting, the amplifier circuit amplifying an electric signal, generated by the conversion circuit, by the gain set by the resistor circuit and outputting the amplified electric signal as a current detection signal; wherein: said conversion circuit (16) and said amplifier circuit (17) are composed of elements of semiconductor material and formed commonly on a semiconductor substrate (100); said conversion circuit (16) and said resistor circuit (21 to 23) of said amplifier circuit are thermally coupled with each other to transfer a temperature change in said conversion circuit caused by a heat generated by a current flowing through said conversion circuit, so that a gain of said amplifier circuit (17) is changed in accordance with the temperature change of said conversion circuit (16) to thereby ensure high accuracy of the output current detection signal even in a case where the temperature change in said conversion circuit causes changes of the electric signal. 2. The current detection circuit according to claim 1, further comprising a switching element (11) formed on said common semiconductor substrate (100) and switches on and off the current flowing to said electric load, wherein said conversion circuit (16) and said resistor circuit (21 to 23) of said amplifier circuit (17) are thermally coupled with each other to transfer a temperature change in said conversion circuit caused by a heat generated by a current flowing through said switching element and said conversion circuit, so that a gain of said amplifier circuit (17) is changed in accordance with the temperature change of said conversion circuit (16) to thereby ensure high accuracy of the output current detection signal even in a case where the temperature change in said conversion circuit causes changes of the electric signal. 3. The current detection circuit according to claim 1, wherein said conversion circuit (16) comprises a plurality of conversion elements (161 to 16n) that convert a current flowing therethrough to a voltage to thereby generate said electric signal; said resistor circuit (21 to 23) of said amplifier circuit (17) comprises a plurality of resistor elements (21 to 23); and said plurality of elements (161 to 16n) of said conversion circuit (16) and said plurality of resistor elements (21 to 23) of said resistor circuit (21 to 23) are formed in proximity to each other on said common semiconductor substrate (100). 4. The current detection circuit according to claim 1, wherein said conversion circuit (16) comprises a plurality of conversion elements (161 to l6n); said resistor circuit (21 to 23) of said amplifier circuit (17) comprises a plurality of resistor elements (21 to 23), wherein the gain of said amplifier circuit (17) is changed in accordance with a temperature and in accordance with characteristics of said resistor circuit, and said plurality of elements (161 to 16n) of said conversion circuit (16) and said plurality of resistor elements (21 to 23) of said resistor circuit (21 to 23) are formed in proximity to each other on said common semiconductor substrate (100). 5. The current detection circuit according to claim 1, wherein said conversion circuit (16) comprises a plurality of conversion elements (161 to l6n); said resistor circuit (21 to 23) of said amplifier circuit (17) comprises a plurality of resistor elements (21 to 23), wherein the gain of said amplifier circuit (17) is changed in accordance with a temperature and in accordance with characteristics of said resistor circuit; at least a part of said plurality of resistor elements (21 to 23) of said amplifier circuit (17) is arranged in between the plurality of elements (161 to 16n) of said conversion circuit. 6. The current detection circuit according to claim 1, wherein said plurality of elements (161 to 16n) which constitutes said conversion circuit (16) and the elements which constitutes said amplifier circuit are resistor elements. 7. An actuator driver unit comprising a current detection circuit as recited in claim 1, further comprising: a switching element (11) that makes and breaks a circuit between a power source (12) and said actuator (15), the actuator (15) to be a target of driving, a control circuit (13) that supplies the control signal to said switching element (11) in accordance with the output of said amplifier circuit (17), wherein said conversion circuit (16) generates said electric signal, which corresponds to a current passing through said actuator (15) by being electrically connected to and disconnected from said power source, by switching-on and-off of said switching element (11); and said amplifier circuit (17) amplifies the electronic signal output by said conversion circuit (16) and corresponding to the current passing through said actuator (15).