Overcurrent protection circuit of power device and semiconductor integrated circuit device
First Claim
1. A circuit for protecting a power device from overcurrent, said power device having a sensing electrode from which a sensing signal related to a main current flowing through a main current path of said power device is obtained, said circuit comprising:
- driver means for receiving an input signal to generate a control signal and for supplying said control signal to a control electrode of said power device;
reference signal generator means for generating first and second reference signals, a level of said second reference signal being higher than a level of said first reference signal;
pulse generator means for generating a pulse in response to activation of said input signal;
selector means for selecting one of said second and first reference signals in response to activation and inactivation of said pulse, respectively, to obtain a selected reference signal; and
comparator means for comparing said sensing signal with said selected reference signal to generate a drive control signal which is supplied to said driver means to disable said driver means.
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Accused Products
Abstract
In an overcurrent protection circuit of a power device, an analog switch (4) connects a negative input of a comparator (3) to a reference voltage VREF1 or another reference voltage VREF2 depending on a control signal (S5) from a timer (5). A positive input of the comparator (3) receives voltage drop value (VS). The timer (5) is triggered by a leading edge of an input signal (IN) to output the control signal (S5) to the analog switch (4). The control signal (S5) directs the analog switch (4) to connect the reference voltage VREF2 to the negative input of the comparator (3) only during a transient state estimated period (T) and to connect the reference voltage VREF1 to the negative input of the comparator (3) out of the transient state estimated period (T).
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Citations
15 Claims
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1. A circuit for protecting a power device from overcurrent, said power device having a sensing electrode from which a sensing signal related to a main current flowing through a main current path of said power device is obtained, said circuit comprising:
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driver means for receiving an input signal to generate a control signal and for supplying said control signal to a control electrode of said power device; reference signal generator means for generating first and second reference signals, a level of said second reference signal being higher than a level of said first reference signal; pulse generator means for generating a pulse in response to activation of said input signal; selector means for selecting one of said second and first reference signals in response to activation and inactivation of said pulse, respectively, to obtain a selected reference signal; and comparator means for comparing said sensing signal with said selected reference signal to generate a drive control signal which is supplied to said driver means to disable said driver means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit for protecting a power device from overcurrent, said power device having a sensing electrode from which a sensing signal related to a main current flowing through a main current path of said power device is obtained, said circuit comprising:
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driver means for receiving an input signal to generate a control signal and for supplying said control signal to a control electrode of said power device; pulse generator means for generating a pulse in response to activation of said input signal; converter means operable to convert said sensing signal into one of first and second objective signals in response to said pulse to obtain a selected objective signal, respectively, a level of said second objective signal being lower than a level of said first objective signal; reference signal generator means for generating a reference signal; and comparator means for comparing said selected objective signal with said reference signal to generate a drive control signal which is supplied to said driver means to disable said driver means. - View Dependent Claims (8, 9, 10, 11)
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12. A circuit for protecting a power device from overcurrent, said power device having a sensing electrode from which a sensing signal related to a main current flowing through a main current path of said power device is obtained, said circuit comprising:
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driver means for receiving an input signal to generate a control signal and for supplying said control signal to a control electrode of said power device; pulse generator means for generating a pulse in response to activation of said input signal; reference signal generator means for generating first and second reference signals, a level of said second reference signal being higher than a level of said first reference signal; first and second comparator means for comparing said sensing signal with said first and second reference signals, respectively; and selector means for selecting one of outputs of said first and second comparator means in response to said pulse to generate a drive control signal which is supplied to said driver means to disable said driver means; wherein said pulse generator means comprises; means for activating said pulse in response to activation of said input signal; and timer means for starting a time count in response to said activation of said input signal and for inactivating said pulse when said time count reaches a predetermined time period value; and wherein said selector means comprises; analog switch means for selecting one of said outputs of said first and second comparator means in response to said pulse to obtain said drive control signal.
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13. A circuit for protecting a power device from overcurrent, said power device having a sensing electrode from which a sensing signal related to a main current flowing through a main current path of said power device is obtained, said circuit comprising:
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driver means for receiving an input signal to generate a control signal and for supplying said control signal to a control electrode of said power device; pulse generator means for generating a pulse in response to activation of said input signal; converter means for converting said sensing signal into first and second objective signals, a level of said second objective signal being higher than a level of said first objective signal; reference signal generator means for generating a reference signal; first and second comparator means for comparing said first and second objective signals with said reference signal to output first and second output signals, respectively; and selector means for selecting one of said first and second output signals in response to said pulse to generate a drive control signal which is supplied to said driver means to disable said driver means. - View Dependent Claims (14, 15)
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Specification