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US 6,472,910 B2Granted
Electrical load driving device
AssigneeDenso Corporation
InventorYukihide Niimi
Life of this patent
Estimating the term…
Abstract
An electrical load driving device is constructed to accurately detect an over-current state in either a high-side output mode or a low-side output mode irrespective of voltage fluctuations of a load power supply. The over-current is detected by a detection voltage which decreases from a battery voltage in proportion to a current flowing through an output transistor being compared with a determination voltage in the high-side output mode. It is detected by a second detection voltage which increases from a ground potential in proportion to the current flowing through the output transistor being compared with a determination voltage in the low-side output mode.
Claims10
An electrical load driving device comprising:
- an output transistor having a first output terminal and a second output terminal connected in series in an electrical current supply path for passing a driving current through an electrical load, the output transistor supplying the driving current to the electrical load by assuming an ON state;
- in accordance with an output mode setting signal, the output transistor being caused to function either as high-side driving means which, with the first output terminal connected to the high-potential side of a load power supply and the second output terminal connected to one terminal of the electrical load having its other terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with a driving signal, passes the driving current to the electrical load, or being caused as low-side driving means which, with the first output terminal connected to the one terminal of the electrical load having its other terminal connected to the high-potential side of the load power supply and the second output terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with the driving signal, draws the driving current from the electrical load;
- first current detection signal generating means for generating as a first current detection signal a voltage dropped from the high-potential side of the load power supply by a voltage proportional to the driving current flowing through the output transistor, when the output transistor is functioning as the high-side driving means;
- first over-current determination voltage generating means for generating as a first over-current determination voltage, the first over-current determination voltage to be compared with the first current detection signal, a voltage dropped from the high-potential side of the load power supply by a predetermined voltage;
- second current detection signal generating means for generating as a second current detection signal a voltage raised from the low-potential side of the load power supply by a voltage proportional to the driving current flowing through the output transistor, when the output transistor is functioning as the low-side driving means;
- second over-current determination voltage generating means for generating as a second over-current determination voltage, the second over-current determination voltage to be compared with the second current detection signal, a voltage raised from the low-potential side of the load power supply by a predetermined voltage;
- and
- over-current detection signal outputting means for comparing the first current detection signal with the first over-current determination voltage and outputting an over-current detection signal indicating that the driving current flowing through the output transistor is excessive when the first current detection signal falls below the first over-current determination voltage when the output transistor is being caused to function as the high-side driving means, and for comparing the second current detection signal with the second over-current determination voltage and outputting the over-current detection signal when the second current detection signal rises above the second over-current determination voltage when the output transistor is being caused to function as the lowside driving means.
5 more elements
An electrical load driving device comprising:
- an output transistor having a first output terminal and a second output terminal connected in series in an electrical current supply path for passing a driving current through an electrical load, the output transistor supplying the driving current to the electrical load by assuming an ON state;
- in accordance with an output mode setting signal, the output transistor being caused to function either as high-side driving means which, with the first output terminal connected to the high-potential side of a load power supply and the second output terminal connected to one terminal of the electrical load having its other terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with a driving signal, passes the driving current to the electrical load, or being caused to function as low-side driving means which, with the first output terminal connected to the one terminal of the electrical load having its other terminal connected to the high-potential side of the load power supply and the second output terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with the driving signal, draws the driving current from the electrical load;
- current detection signal generating means for generating a current detection voltage signal indicative of the driving current flowing in the output transistor, when the output transistor is functioning in either one of a mode in which the output transistor is caused to function as the high-side driving means or a mode in which the output transistor is caused to function as the low-side driving means;
- over-current determination voltage generating means for generating an over-current determination voltage to be compared with the current detection voltage signal;
- and
- over-current detection means for comparing the current detection voltage signal with the over-current determination voltage and outputting an over-current detection signal indicating that the driving current flowing through the output transistor is excessive whether the output transistor is caused to function as the high-side driving means or the low-side driving means.
3 more elements
A method of driving an electrical load, the method comprising:
- providing an output transistor having a first output terminal and a second output terminal connected in series in an electrical current supply path for passing a driving current through the electrical load, the output transistor supplying the driving current to the electrical load by assuming an ON state;
- in accordance with an output mode setting signal, causing the output transistor to function either as a high-side driver which, with the first output terminal connected to the high-potential side of a load power supply and the second output terminal connected to one terminal of the electrical load having its other terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with a driving signal, passes the driving current to the electrical load, or causing the output transistor to function as a low-side driver which, with the first output terminal connected to the one terminal of the electrical load having its other terminal connected to the high-potential side of the load power supply and the second output terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with the driving signal, draws the driving current from the electrical load;
- generating as a first current detection signal a voltage dropped from the high-potential side of the load power supply by a voltage proportional to the driving current flowing through the output transistor, when the output transistor is functioning as the high-side driver;
- generating as a first over-current determination voltage, the first over-current determination voltage to be compared with the first current detection signal, a voltage dropped from the high-potential side of the load power supply by a predetermined voltage;
- generating as a second current detection signal a voltage raised from the low-potential side of the load power supply by a voltage proportional to the driving current flowing through the output transistor, when the output transistor is functioning as the low-side driver;
- generating as a second over-current determination voltage, the second over-current determination voltage to be compared with the second current detection signal, a voltage raised from the low-potential side of the load power supply by a predetermined voltage;
- and
- comparing the first current detection signal with the first over-current determination voltage and outputting an over-current detection signal indicating that the driving current flowing through the output transistor is excessive when the first current detection signal falls below the first over-current determination voltage when the output transistor is being caused to function as the high-side driver, and for comparing the second current detection signal with the second over-current determination voltage and outputting the over-current detection signal when the second current detection signal rises above the second over-current determination voltage when the output transistor is being caused to function as the low-side driver.
5 more elements
A method of driving an electrical load comprising:
- providing an output transistor having a first output terminal and a second output terminal connected in series in an electrical current supply path for passing a driving current through the electrical load, the output transistor supplying the driving current to the electrical load by assuming an ON state;
- in accordance with an output mode setting signal, causing the output transistor to function either as a high-side driver which, with the first output terminal connected to the high-potential side of a load power supply and the second output terminal connected to one terminal of the electrical load having its other terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with a driving signal, passes the driving current to the electrical load, or causing the output transistor to function as a low-side driver which, with the first output terminal connected to the one terminal of the electrical load having its other terminal connected to the high-potential side of the load power supply and the second output terminal connected to the low-potential side of the load power supply, by assuming the ON state in accordance with the driving signal, draws the driving current from the electrical load;
- generating a current detection voltage signal indicative of the current flowing in the output transistor, when the output transistor is functioning in either a mode in which the output transistor is caused to function as the high-side driver or a mode in which the output transistor is caused to function as the low-side driver;
- generating an over-current determination voltage to be compared with the current detection voltage signal;
- and
- comparing the current detection voltage signal with the over-current determination voltage and outputting an over-current detection signal indicating that the driving current flowing through the output transistor is excessive.
3 more elements
Dependencies are inferred from the claim text.