WO2005112217A1 - 過電流検出回路及びこれを有する電源装置 - Google Patents
過電流検出回路及びこれを有する電源装置 Download PDFInfo
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- WO2005112217A1 WO2005112217A1 PCT/JP2005/008967 JP2005008967W WO2005112217A1 WO 2005112217 A1 WO2005112217 A1 WO 2005112217A1 JP 2005008967 W JP2005008967 W JP 2005008967W WO 2005112217 A1 WO2005112217 A1 WO 2005112217A1
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- transistor
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- mos transistor
- electrode
- overcurrent
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
- H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/18—Modifications for indicating state of switch
Definitions
- the present invention relates to an overcurrent detection circuit used for a power supply device or the like. More particularly, the present invention relates to an overcurrent detection circuit including a MOS transistor (insulated gate type field effect transistor) as a switching element for outputting a current to a load. Further, the present invention relates to a power supply device having the overcurrent detection circuit.
- MOS transistor insulated gate type field effect transistor
- FIG. 5 As a conventional overcurrent detection circuit including a MOS transistor as a switching element, there is one as shown in FIG.
- a power supply voltage 105 is supplied to the source electrode of a P-channel (P-type semiconductor) power MOS transistor 100, and its drain electrode is connected to one end of a load 103 via a detection resistor 101. It is connected. The other end of the load 103 is grounded!
- connection point between the drain electrode of the power MOS transistor 100 and the detection resistor 101 is connected to the base electrode of the NPN transistor 102, and the connection point between the detection resistor 101 and the load 103 is connected to the emitter electrode of the transistor 102.
- the power supply voltage 105 is connected to the collector electrode of the transistor 102 via the resistor 104, and a pulse voltage for turning on and off the power MOS transistor 100 is supplied to the gate electrode of the power MOS transistor 100 from the outside. Is done.
- FIG. 6 there is one as shown in FIG. 6 (for example, see Patent Document 1).
- a power supply voltage 110 is supplied to a drain electrode of an N-channel (N-type semiconductor) power MOS transistor 112, and a source electrode thereof is connected to one end of a load 116. The other end of the load 116 is grounded.
- a power supply voltage 110 is supplied to a drain electrode of an N-channel (N-type semiconductor) detection MOS transistor 111, and its source electrode is connected to one end of a detection resistor 114 and a non-inverting input terminal (+) of a comparator 115. Connected in common.
- the other end of the detection resistor 114 is connected to a connection point between the source electrode of the power MOS transistor 112 and the load 116, and to the inverting input terminal (-) of the comparator 115.
- the gate electrodes of the power MOS transistor 112 and the detection MOS transistor 111 are commonly connected to a terminal 113.
- the terminal 113 has a pulse voltage for controlling on / off of both the power MOS transistor 112 and the detection MOS transistor 111. Is supplied from outside.
- the power MOS transistor 112 has a large number (k; k is an integer of 2 or more, for example, 100) of unit cell transistors, and connects their drain, source, and gate in parallel. Thereby, it is formed as a single MOS transistor.
- the detection MOS transistor 111 is formed of, for example, one and the same unit cell transistor! RU
- the area ratio of the channel between the power MOS transistor 112 and the detection MOS transistor 111 is 100: 1, and the ratio of the current flowing through these transistors is also 100: 1 (the configuration example shown in FIG. It is referred to as "first example of Patent Document 1."
- the overcurrent detection circuit configured as described above, when an overcurrent flows through the power MOS transistor 112 and a current of 1Z100 flows through the detection MOS transistor, a comparison is made between the two terminals of the detection resistor 114. A voltage drop that is higher than the reference voltage determined inside the unit 115 occurs. At this time, the comparator 115 outputs an overcurrent detection signal indicating that an overcurrent is flowing to the power MOS transistor 112, and notifies a control unit (not shown) of the overcurrent state of the power MOS transistor 112.
- Patent Document 1 discloses the following configuration example! A large number of unit MOS transistor elements are arranged in parallel, and the sources, gates, and drains of the unit elements are connected in parallel by wiring to derive the source, gate, and drain, and a single element Detects the voltage drop across both ends of the wiring resistance of the source or drain wiring due to the parallel connection of the output power MOS transistor and the source or drain of the unit element, and detects the overcurrent flowing through the power MOS transistor.
- a semiconductor device in which an overcurrent detection circuit unit and the overcurrent detection circuit are formed in the same element this configuration example is hereinafter referred to as "second example of Patent Document 1").
- Patent Document 1 Registered Utility Model No. 2525470 (Japan)
- a detection resistor 101 is provided between the power MOS transistor 100 and the load 103 in order to detect an overcurrent state of the power MOS transistor 100.
- a power loss occurs in the detection resistor 101, deteriorating the power efficiency of the entire circuit and increasing the problem of heat generation.
- the resistance value has a large temperature dependency (for example, about 2000 ppm Z ° C.). That is, the temperature coefficient of the detection resistor 101 increases.
- the threshold value of the current for detecting the overcurrent state of the power MOS transistor 100 has a large temperature dependence, and as a result, the detection error of the overcurrent detection (hereinafter, simply referred to as “detection error”) increases.
- detection error increases because the base-emitter voltage at which the transistor 102 is turned on has a large temperature dependency.
- the heat generated by the detection resistor 101 affects the resistance value of the detection resistor 101 and the base-emitter voltage at which the transistor 102 is turned on, so that the detection error further increases.
- the area ratio between the channels of the power MOS transistor 112 and the detection MOS transistor 111 is set to k: 1 (100: 1), and the current ratio flowing through these transistors is set to k: 1. Even if it is measured, the voltage between the drain and the source electrode in the detection MOS transistor 111 becomes smaller than the voltage between the drain and the source electrode in the power MOS transistor 112 due to the voltage drop generated in the detection resistor 114. Because the on-resistance (resistance between the drain and source electrode when the transistor is on; resistance of the channel) becomes larger than ideal (ideally k times the on-resistance of the power MOS transistor 112), the actual The current ratio is not as designed. That is, due to the Early effect, the actual current ratio does not become as designed, and this also causes a large detection error.
- the voltage between the gate and the source in the detection MOS transistor 111 becomes smaller than the voltage between the gate and the source in the power MOS transistor 112 due to the voltage drop generated in the detection resistor 114. Also according to this, the on-resistance of the detection MOS transistor becomes larger than ideal, and the detection error further increases.
- the wiring resistance of the source or drain is used as the detection resistance.
- the design is difficult. The freedom is lost.
- the present invention eliminates the detection error caused by the early effect while maintaining high power efficiency of the entire circuit, and has high accuracy overcurrent detection with little temperature dependence of the detection error. It is intended to provide a circuit. Another object of the present invention is to provide a power supply device having the overcurrent detection circuit.
- an overcurrent detection circuit is an overcurrent detection circuit that detects an overcurrent state of an output transistor that outputs a current to a load and outputs an overcurrent detection signal.
- a detection transistor connected in parallel with the output transistor; a constant current circuit connected to one end of the detection transistor for flowing a predetermined constant current to the detection transistor; and flowing a current to the load. Based on a comparison result between a voltage generated between the first electrode and the second electrode of the output transistor and a voltage generated between the first electrode and the second electrode of the detection transistor when the constant current flows.
- a comparator for outputting a current detection signal.
- the comparator when detecting an overcurrent state, applies a current to the load.
- the magnitude of a voltage generated between the first electrode and the second electrode of the output transistor by flowing the current is compared with a voltage generated between the first electrode and the second electrode of the detection transistor by the flow of the constant current.
- the comparator determines "the voltage generated between the first electrode and the second electrode of the output transistor" and "the detection transistor". This is the case when it is determined that the voltage between the first electrode and the second electrode has become equal. No deviation of the actual current ratio from the designed value occurs. That is, since a detection error due to the Early effect hardly occurs, overcurrent detection with high accuracy is possible.
- a detection resistor (detection resistor 101 and the like) which is indispensable for detection of an overcurrent state is replaced with the above-described configuration according to the present invention. Since the configuration is not used, there is no large temperature dependence of the detection error due to the large temperature coefficient. That is, it is possible to realize overcurrent detection in which the temperature dependence of the detection error is small (the increase in the detection error due to the temperature change).
- the overcurrent detection circuit according to the present invention and the power supply device including the overcurrent detection circuit have improved reliability, and can reduce the mounting area and cost.
- the overcurrent detection circuit is an overcurrent detection circuit that detects an overcurrent state of an output transistor that outputs a current from a second electrode to a load and outputs an overcurrent detection signal.
- the first electrode and the control electrode are connected to a detection transistor commonly connected to the first electrode and the control electrode of the output transistor, respectively, and the second electrode of the detection transistor is connected to the detection transistor.
- a constant current circuit that supplies a predetermined constant current; and a comparator that outputs the overcurrent detection signal based on a comparison result between the potential of the second electrode of the output transistor and the potential of the second electrode of the detection transistor.
- the comparator compares the potential of the second electrode of the output transistor with the potential of the second electrode of the detection transistor. Further, the first electrode and the control electrode of the detection transistor are connected to the first electrode and the control electrode of the output transistor, respectively.
- the comparator determines “the voltage generated between the first electrode and the second electrode of the output transistor” and “the detection transistor”. This is the case when it is determined that the voltage between the first electrode and the second electrode has become equal. No deviation of the actual current ratio from the designed value occurs. That is, since a detection error due to the Early effect hardly occurs, overcurrent detection with high accuracy is possible.
- a detection resistor (detection resistor 101 and the like) which is indispensable for detecting an overcurrent state is replaced with the above-described detection device according to the present invention. Since the configuration is not used, there is no large temperature dependence of the detection error due to the large temperature coefficient. That is, overcurrent detection in which the temperature dependence of the detection error is small can be realized.
- the overcurrent detection circuit according to the present invention and the power supply device including the overcurrent detection circuit have improved reliability, and can reduce the mounting area and cost.
- the output transistor and the detection transistor are a power MOS transistor and a detection MOS transistor, respectively, and the current value of the constant current is a predetermined value of the power MOS transistor. It may be set based on the maximum output current value, the on-resistance of the power MOS transistor, and the on-resistance of the detection MOS transistor.
- the “maximum output current value” is a threshold value for detecting an overcurrent state of the power MOS transistor, and is predetermined according to the characteristics of the power MOS transistor. Value. If the magnitude of the current flowing through the power MOS transistor is less than the maximum output current value, it is detected that the power MOS transistor is not in an overcurrent state, while the magnitude of the current flowing through the power MOS transistor is less than the maximum output current value. If so, the overcurrent detection circuit is designed so that "the power MOS transistor is in an overcurrent state" is detected.
- the output transistor is a power MOS transistor, and has n (n is an integer of 2 or more) unit cell transistors, and has drains of the n unit cell transistors.
- a source and a gate are connected in parallel to form a single MOS transistor
- the detection transistor is a detection MOS transistor, and is formed by a single unit cell transistor.
- m (m is an integer of 2 or more; m ⁇ n) unit cell transistors, and the drain, source, and gate of the m unit cell transistors are connected in parallel to form a single MOS transistor.
- a unit cell transistor forming the power MOS transistor and a unit cell forming the detection MOS transistor All the transistors are formed on the same semiconductor substrate by using the same manufacturing process.
- the temperature coefficient of the on-resistance of the power MOS transistor and the detection MOS transistor becomes substantially the same, so that the temperature dependence of the threshold value of the current for detecting the overcurrent state is reduced (temperature change). , The fluctuation of the threshold value is reduced). That is, the temperature dependency of the detection error and the overcurrent detection can be realized.
- the ratio of the actual resistance of the on-resistance of the MOS transistor for detection to the resistance of the on-resistance of the power MOS transistor is approximately the same as the design value. It becomes possible.
- a current obtained by applying a predetermined reference voltage to a combined resistance of a resistor having a positive temperature coefficient and a resistor having a negative temperature coefficient is defined as the constant current, It is good to configure so that the resistance value of the combined resistance is constant regardless of the temperature change
- the current value of the constant current is constant regardless of a temperature change.
- the temperature dependence of the detection error of the overcurrent detection can be further reduced.
- a power supply device includes the overcurrent detection circuit, the output transistor, and a smoothing circuit that smoothes a voltage on an output side of the output transistor and outputs the voltage to the load.
- the power supply device includes a voltage detection circuit that outputs a voltage corresponding to a voltage supplied to the load, and the output transistor and the detection transistor according to an output of the voltage detection circuit. And a control unit for controlling the control.
- control unit may be controlled according to the output of the comparator.
- the overcurrent detection circuit of the present invention it is possible to eliminate the detection error due to the Early effect while maintaining high power efficiency of the entire circuit, and to reduce the temperature dependence of the detection error. Character can be reduced.
- FIG. 1 is a circuit diagram of a power supply device including an overcurrent detection circuit according to an embodiment of the present invention.
- FIG. 2 is a detailed circuit diagram of a power MOS transistor in FIG. 1.
- FIG. 3 is a detailed circuit diagram of the constant current circuit in FIG. 1.
- FIG. 4 is a detailed circuit diagram of the constant voltage generation circuit in FIG.
- FIG. 5 is a circuit diagram showing a first example of a conventional overcurrent detection circuit.
- FIG. 6 is a circuit diagram showing a second example of a conventional overcurrent detection circuit.
- FIG. 1 is a circuit configuration diagram of a power supply device 1 including an overcurrent detection circuit 14 according to an embodiment of the present invention.
- FIG. 2 is a detailed circuit configuration diagram of the power MOS transistor 2 in FIG.
- the power supply voltage Vcc is supplied to the source electrode of the P-channel (P-type semiconductor) power MOS transistor 2 (output transistor), and the drain electrode of the power MOS transistor 2 is grounded.
- the power source of the connected diode 10 and one end of the inductor 11 are connected.
- the other end of the inductor 11 is grounded via a parallel circuit of the load 6 and the capacitor 12, and is also grounded via a series circuit of the resistors 8 and 9.
- the power MOS transistor 2 outputs current (supplies power) to the load 6 from the drain electrode.
- the diode 10, the inductor 11, and the capacitor 12 form a smoothing circuit that smoothes the output voltage (drain electrode voltage) of the power MOS transistor 2 and outputs the smoothed voltage to the load 6.
- the power supply voltage Vcc is supplied to the source electrode of the P-channel detection MOS transistor 3 (detection transistor), and its drain electrode is connected to one end of the constant current circuit 4 and the non-connected terminal of the comparator 5 which is a comparator. Connected to inverting input terminal (+). The other end of the constant current circuit 4 is grounded, and the constant current circuit 4 supplies a constant current Ic between the source and drain electrodes of the detection MOS transistor 3 when the detection MOS transistor 3 is on. Shed.
- connection point between the power MOS transistor 2 and the power source of the diode 10 is connected to the inverting input terminal (1) of the comparator 5.
- the connection point between the resistor 8 and the resistor 9 is connected to the control unit 7, and the voltage supplied to the load 6 is divided by a series circuit of the resistor 8 and the resistor 9, and the divided voltage is The value is given to the control unit 7. That is, the resistors 8 and 9 function as a voltage detection circuit that outputs a voltage corresponding to the voltage supplied to the load 6 to the control unit 7.
- the output of the comparator 5 is provided to the control unit 7 as an overcurrent detection signal indicating the overcurrent state of the power MOS transistor 2. Specifically, when the voltage output from the comparator 5 is a high signal (high-potential signal), it indicates that the power MOS transistor 2 is in an overcurrent state, and when the voltage output from the comparator 5 is a low signal (low-potential signal), Indicates normal status (not overcurrent status).
- the comparator 5 compares the potential of the drain electrode of the power MOS transistor 2 with the potential of the drain electrode of the detection MOS transistor 3, and outputs the comparison result as an overcurrent detection signal.
- the “overcurrent state” means a state where the current value of the drain current of the power MOS transistor 2 exceeds the maximum output current value of the power MOS transistor 2.
- the “maximum output current value” is a threshold value for detecting an overcurrent state of the power MOS transistor 2, and is a value predetermined according to the characteristics of the power MOS transistor 2.
- the overcurrent detection circuit 14 is designed so that “the power MOS transistor 2 is in an overcurrent state” is detected.
- the overcurrent detection circuit 14 may include the power MOS transistor 2 including the detection MOS transistor 3, the constant current circuit 4, and the comparator 5. Hereinafter, the description will be made assuming that the overcurrent detection circuit 14 includes the power MOS transistor 2.
- the output of the control unit 7 is commonly connected to the gate electrodes of the power MOS transistor 2 and the detection MOS transistor 3.
- the control unit 7 monitors the overcurrent state of the power MOS transistor 2 with reference to the overcurrent detection signal, detects the voltage applied to the load 6 from the potential at the midpoint between the resistors 8 and 9, and detects the load 6
- a pulsed voltage is supplied to each gate electrode of the power MOS transistor 2 and the detection MOS transistor 3 so that the voltage applied to the
- the series circuit of the resistor 8 and the resistor 9 is provided to detect the voltage applied to the load 6, and its combined resistance value is sufficiently larger than the resistance value (or impedance) of the load 6 ( Therefore, the power loss in the series circuit is negligibly small).
- the power MOS transistor 2 includes a large number (n; n is an integer of 2 or more) of unit cell transistors (the unit cell transistors are also insulated gate type field effect transistors).
- n is an integer of 2 or more
- the power MOS transistor 2 is formed as a single MOS transistor by connecting the drain, source, and gate of each unit cell transistor in parallel. That is, the electrodes of the unit cell transistors Trl, Tr2, ⁇ , Trn connected in parallel with the drain, source and gate are respectively connected to the drain electrode 15, source electrode 16 and gate electrode 17 of the power MOS transistor 2.
- the detection MOS transistor 3 is formed only by a single unit cell transistor. Like the power MOS transistor 2, the detection MOS transistor 3 also has a plurality (m; m is an integer of 2 or more and m ⁇ n) of unit cell transistors (not shown). The drain, source and gate of each unit cell transistor may be connected in parallel to form a single MOS transistor. That is, The electrodes in which the drains, sources and gates of the m unit cell transistors are connected in parallel may be used as the drain electrode, source electrode and gate electrode of the detection MOS transistor 3, respectively.
- the unit cell transistors constituting the power MOS transistor 2 and the unit cell transistors constituting the detection MOS transistor 3 are all formed on the same semiconductor substrate by using the same manufacturing process. That is, since all unit cell transistors have the same structure, the temperature coefficient of the resistance value of each on-resistance is substantially the same, and the gate-source electrode voltage, the drain-source electrode voltage, and the ambient temperature are the same. Under these conditions (these conditions are hereinafter referred to as “the same conditions”), the resistance values of the on-resistances are substantially the same.
- the power MOS transistor 2 also has a parallel connection power of 1000 unit cell transistors and the detection MOS transistor 3 has a single unit cell transistor power.
- the area ratio of the channels of the power MOS transistor 2 and the detection MOS transistor 3 is 1000: 1, the ratio of the on-resistance values is 1: 1000.
- the maximum output current value of power MOS transistor 2 is defined as Io. That is, power MOS tiger max
- comparator 5 When the drain current of transistor 2 exceeds the maximum output current value Io, comparator 5
- One MOS transistor 2 is in an overcurrent state and outputs a high signal to the control unit 7.
- the comparator 5 outputs a low signal.
- the comparator 5 Since the voltage between the in-source electrodes becomes larger than the voltage between the drain and the source electrodes of the detection MOS transistor 3, the comparator 5 outputs a high signal.
- control unit 7 When the control unit 7 receives the high signal from the comparator 5, the control unit 7 recognizes that the power MOS transistor 2 is in an overcurrent state, and outputs a voltage for turning off the power MOS transistor 2 to the power MOS transistor 2. Applied to the gate electrode of transistor 2. This prevents the power MOS transistor 2, diode 10, inductor 11 and load 6 from being damaged.
- the control unit 7 detects an overcurrent state of the power MOS transistor 2, a release signal is input from the outside or the power supply voltage Vcc is turned on again (the supply of the power supply voltage Vcc is interrupted once). The power MOS transistor 2 remains off until the power MOS transistor 2 is turned on again.
- the degree of the detection error becomes a problem when the drain current of the power MOS transistor 2 is near the maximum output current value Io (for example, 100% to 120% of Io).
- the voltage between the gate and source electrodes of the power MOS transistor 2 and the detection MOS transistor 3 are equal. Further, when the drain current of the power MOS transistor 2 is equal to the maximum output current value Io, the voltages between the drain and source electrodes of the power MOS transistor 2 and the detection MOS transistor 3 are equal, so that the comparator 5 The potentials of the non-inverting input terminal (+) and the inverting input terminal (-) are equal.
- the ratio of the on-resistances of the power MOS transistor 2 and the detection MOS transistor 3 is exactly 1: 1000 (because an error due to the Early effect can be eliminated). That is, no detection error occurs due to the Early effect seen in the configuration and the like described in Patent Document 1. Further, as described above, since the temperature coefficient of the resistance value of the on-resistance of these transistors is substantially the same, the temperature dependence of the threshold value of the current for detecting the overcurrent state is reduced. Few (the fluctuation of the threshold value due to temperature change is small).
- the overcurrent detection circuit 14 and the power supply device 1 having the same it is possible to detect the overcurrent with extremely high accuracy and small temperature dependency as compared with the related art.
- the error (including temperature dependence) is mainly due to the relative variation of the on-resistance of the unit cell transistor.
- the maximum output current value I taking into account the detection error. I have to set max to a small value. Then, although the power MOS transistor 2 and the like can still operate safely, the power MOS transistor 2 is cut off because it can be in an overcurrent state.
- the product can be reduced and the cost can be reduced.
- FIG. 3 shows a specific electrical configuration of the constant current circuit 4 in FIG. Constant voltage generator
- the reference voltage Vref output from the raw circuit 25 is connected to the base of a PNP transistor 23, and its emitter is commonly connected to one end of the constant current circuit 24 and the base of the NPN transistor 20.
- the collector of the transistor 23 is grounded, and the other end of the constant current circuit 24 is supplied with the power supply voltage Vcc.
- the emitter of the transistor 20 is grounded via a series circuit of the resistor 21 and the resistor 22, and the collector thereof is connected to the drain electrode of the MOS transistor 3 for detection. That is, the collector current and the constant current Ic of the transistor 20 are obtained.
- the value obtained by dividing the reference voltage Vref by the resistance value of the combined resistance of the resistors 21 and 22 is the current value of the constant current Ic.
- the resistor 21 and the resistor 22 are formed on the semiconductor substrate by diffusion of impurities or the like. At this time, by appropriately selecting the impurities, the resistance value of the combined resistance of the resistors 21 and 22 is formed to be constant regardless of the temperature change.
- the resistance values of the resistors 21 and 22 at room temperature are 10 k ⁇ (kiloohm) and 20 k ⁇ , respectively, and the temperature coefficients of the resistors 21 and 22 are as follows. + 2000ppmZ each. C,-1000 ppmZ. Set to C.
- the current obtained by applying the reference voltage Vref to the combined resistance of the resistor 21 having a positive temperature coefficient and the resistor 22 having a negative temperature coefficient is defined as a constant current Ic.
- resistors 21 and 22 may be carbon film resistors, metal film resistors, or the like, which need not necessarily be formed on the semiconductor substrate by diffusion of impurities or the like.
- FIG. 4 shows an example of a circuit configuration of the constant voltage generation circuit 25.
- 31 PNP transistors In this case, the base and the collector are connected, and the power supply voltage Vcc is applied to the emitter.
- the base of the PNP transistor 32 is connected to the base of the transistor 31, and the power supply voltage Vcc is applied to the emitter.
- the base of the PNP transistor 33 is connected to the collector of the transistor 32, and the power supply voltage Vcc is applied to the emitter.
- the NPN transistor 34 the base is connected to the collector of the transistor 33, the emitter is grounded via the resistor 37, and the collector is connected to the collector of the transistor 31.
- the base is connected to the collector of the transistor 33, the emitter is connected to the emitter of the transistor 34 via the resistor 36, and the collector is connected to the collector of the transistor 32. Then, the voltage is output as a reference voltage Vref at a connection point between the collector of the transistor 33, the base of the transistor 34, and the base of the transistor 35.
- the reference voltage Vref is set based on a band gap voltage of a semiconductor (1.205 [V] in the case of silicon). Therefore, by using such a constant voltage generation circuit 25 in the constant current circuit 4, the temperature dependence of the current value of the constant current Ic can be made extremely small.
- FIG. 1 shows an embodiment in which the source electrode and the gate electrode of the power MOS transistor 2 and the detection MOS transistor 3 are commonly connected.
- a voltage obtained by subtracting the source-drain electrode voltage of the power MOS transistor 2 from the power supply voltage Vcc is applied to the inverting input terminal (1) of the comparator 5, and the non-inverting input terminal (+) is applied to the non-inverting input terminal (+).
- a voltage obtained by subtracting the voltage between the source and drain electrodes of the detection MOS transistor 3 from the power supply voltage Vcc is applied.
- the comparator 5 compares the voltage V generated between the source and drain electrodes of the (Specifically, when it becomes larger than v,
- the comparator 5 outputs an overcurrent detection signal.
- the overcurrent detection circuit according to the present invention can be variously modified.
- the present invention is not limited to the power supply device 1 shown in FIG. 1, but is applicable to a power supply device having various switching regulator ⁇ DC-DC converters and the like. Furthermore, the present invention is also applicable to a power supply device provided with a series regulator (dropper-type regulator) such as a three-terminal regulator.
- a series regulator dropper-type regulator
- the first electrode, the second electrode, and the control electrode of the power MOS transistor according to the present invention mean the source electrode, the drain electrode, and the gate electrode of the power MOS transistor 2, respectively, in FIG.
- the first electrode, the second electrode, and the control electrode of the detection MOS transistor mean the source electrode, the drain electrode, and the gate electrode of the detection MOS transistor 3 in FIG.
- the first electrode and the second electrode of the power MOS transistor according to the present invention may mean the drain electrode and the source electrode of the power MOS transistor, respectively.
- the first electrode and the second electrode of the detection MOS transistor according to the present invention may mean the drain electrode and the source electrode of the detection MOS transistor, respectively.
- both the power MOS transistor 2 and the detection MOS transistor 3 are constituted by unit cell transistors having the same structure, so that the power MOS transistor 2 and the detection MOS transistor 3
- the ratio of the on-resistance to the MOS transistor 3 was controlled (1: 1000 in the above embodiment)
- the ratio of those WZLs without using the unit cell transistors W: channel width, L: : Channel length
- the ratio of the on-resistance of the power MOS transistor 2 and the detection MOS transistor 3 may be controlled.
- the channel widths of the power MOS transistor 2 and the detection MOS transistor 3 are set to W and W, respectively.
- the resistance value of the on-resistance of the power MOS transistor 2 and the detection MOS transistor 3 becomes 1: 1000.
- the power MOS transistor 2 composed of a MOS transistor is used as an output transistor
- the detection MOS transistor 3 composed of a MOS transistor is used as a detection transistor.
- the transistor 2 and the detection MOS transistor 3 can be replaced with a PNP-type output bipolar transistor (output transistor) and a PNP-type detection bipolar transistor (detection transistor), respectively.
- the configuration needs to be made in consideration of the base current of the bipolar transistor.
- the configuration can be the same as that of the above embodiment.
- the power MOS transistor 2 is replaced with the output bipolar transistor, and the source electrode, the drain electrode and the gate electrode of the power MOS transistor 2 are respectively replaced by the emitter electrode and the collector of the output bipolar transistor.
- the detection MOS transistor 3 is replaced with the above detection bipolar transistor, and the source electrode, drain electrode and gate electrode of the detection MOS transistor 3 are replaced with the emitter electrode of the detection bipolar transistor, respectively. And a collector electrode and a base electrode.
- the output bipolar transistor is composed of a large number (p; n is an integer of 2 or more) of unit cell bipolar transistors, and the collector, emitter and base of each unit cell bipolar transistor are formed. Each is connected in parallel to form a single bipolar transistor, and the detection bipolar transistor is composed of a single unit cell bipolar transistor, or a plurality (q; q is an integer of 2 or more, p > q), the collector, emitter and base of each unit cell bipolar transistor are connected in parallel to form a single bipolar transistor.
- the unit cell bipolar transistors are all manufactured on the same semiconductor It should be formed using a fabrication process.
- the output bipolar transistor and the detection bipolar transistor may not be configured using unit cell bipolar transistors, and the driving capabilities of the respective bipolar transistors may be appropriately set.
- the output bipolar transistor may be manufactured by controlling each emitter area or the like so that the driving capability of the output bipolar transistor is 1000 times the driving capability of the detection bipolar transistor.
- the present invention is suitable for a power supply device, a high-side switch, and the like that require an overcurrent detection circuit that has a small absolute detection error ignoring a temperature change and has a small detection error variation due to a temperature change. It is suitable for an in-vehicle power supply device that requires high-accuracy overcurrent detection at a temperature (for example, ⁇ 40 ° C. to 125 ° C.).
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Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/597,012 US20070229041A1 (en) | 2004-05-18 | 2005-05-17 | Excess Current Detecting Circuit and Power Supply Device Provided with it |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2004-147290 | 2004-05-18 | ||
JP2004147290A JP2005333691A (ja) | 2004-05-18 | 2004-05-18 | 過電流検出回路及びこれを有する電源装置 |
Publications (1)
Publication Number | Publication Date |
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WO2005112217A1 true WO2005112217A1 (ja) | 2005-11-24 |
Family
ID=35394466
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2005/008967 WO2005112217A1 (ja) | 2004-05-18 | 2005-05-17 | 過電流検出回路及びこれを有する電源装置 |
Country Status (6)
Country | Link |
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US (1) | US20070229041A1 (ja) |
JP (1) | JP2005333691A (ja) |
KR (1) | KR20070009712A (ja) |
CN (1) | CN1954469A (ja) |
TW (1) | TW200540431A (ja) |
WO (1) | WO2005112217A1 (ja) |
Families Citing this family (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100483905C (zh) * | 2005-12-21 | 2009-04-29 | 鸿富锦精密工业(深圳)有限公司 | 电源供应电路 |
JP4878181B2 (ja) * | 2006-03-06 | 2012-02-15 | 株式会社リコー | 電流検出回路および該電流検出回路を利用した電流モードdc−dcコンバータ |
JP5022668B2 (ja) * | 2006-10-25 | 2012-09-12 | オンセミコンダクター・トレーディング・リミテッド | Dc/dcコンバータ |
KR100836900B1 (ko) * | 2007-02-09 | 2008-06-11 | 한양대학교 산학협력단 | 전류 감지 회로 |
JP2008276611A (ja) * | 2007-05-01 | 2008-11-13 | Nec Electronics Corp | 過電流保護回路 |
US8174251B2 (en) | 2007-09-13 | 2012-05-08 | Freescale Semiconductor, Inc. | Series regulator with over current protection circuit |
US7576526B2 (en) | 2008-01-16 | 2009-08-18 | Freescale Semiconductor, Inc | Overcurrent detection circuit |
JP5129701B2 (ja) * | 2008-09-12 | 2013-01-30 | ルネサスエレクトロニクス株式会社 | 過電流検出回路 |
JP5332590B2 (ja) * | 2008-12-22 | 2013-11-06 | 株式会社リコー | 電流検出回路および該電流検出回路を用いたスイッチング電源ならびに電子機器 |
JP5434170B2 (ja) * | 2009-03-17 | 2014-03-05 | 株式会社リコー | 過電流保護装置 |
TW201040544A (en) * | 2009-05-01 | 2010-11-16 | Linear Artwork Inc | Sensing system and its method |
DE112010003655B4 (de) * | 2009-10-20 | 2015-12-31 | Mitsubishi Electric Corporation | Fehler-Detektionsvorrichtung für eine Halbleitervorrichtung |
GB2480648B (en) * | 2010-05-26 | 2013-02-20 | Ge Aviat Systems Ltd | Measuring transient electrical activity in aircraft power distribution systems |
JP5581907B2 (ja) | 2010-09-01 | 2014-09-03 | 株式会社リコー | 半導体集積回路及び半導体集積回路装置 |
JP5496038B2 (ja) * | 2010-09-22 | 2014-05-21 | 三菱電機株式会社 | Dc−dcコンバータ |
JP2012135143A (ja) * | 2010-12-22 | 2012-07-12 | Howa Mach Ltd | 負荷制御装置 |
EP2763318B1 (en) * | 2011-09-29 | 2021-03-17 | Fuji Electric Co., Ltd. | Load driving circuit |
CN103134977B (zh) * | 2011-11-28 | 2015-08-19 | 统达能源股份有限公司 | 大电流侦测装置及其侦测方法 |
US11159009B2 (en) | 2013-04-01 | 2021-10-26 | Qualcomm Incorporated | Voltage regulator over-current protection |
CN103956708B (zh) * | 2014-04-21 | 2016-09-07 | 杭州电子科技大学 | 低压直流负载过载测控电路 |
KR102245472B1 (ko) * | 2014-08-18 | 2021-04-29 | 삼성디스플레이 주식회사 | Dc-dc 컨버터 및 이를 포함하는 유기 발광 표시 장치 |
US9678111B2 (en) * | 2015-10-07 | 2017-06-13 | Nxp B.V. | Current sensing with compensation for component variations |
US9634657B1 (en) * | 2015-12-01 | 2017-04-25 | General Electric Company | System and method for overcurrent protection for a field controlled switch |
JP6629593B2 (ja) * | 2015-12-28 | 2020-01-15 | ローム株式会社 | 電源回路およびその制御回路、制御方法、ならびにそれを用いた電子機器 |
TWI603563B (zh) | 2016-05-05 | 2017-10-21 | 創惟科技股份有限公司 | 電力供應控制單元、控制模組、控制裝置及其控制方法 |
CN106848998B (zh) * | 2017-02-28 | 2019-05-24 | 浙江大华技术股份有限公司 | 一种电源输出保护电路及装置 |
US10903355B1 (en) | 2019-11-27 | 2021-01-26 | Analog Devices International Unlimited Company | Power switch arrangement |
CN113497435A (zh) * | 2020-04-08 | 2021-10-12 | 法雷奥汽车空调湖北有限公司 | 过电流保护*** |
JP2022136418A (ja) | 2021-03-08 | 2022-09-21 | ローム株式会社 | 過電流保護回路、電源制御装置、反転型スイッチング電源 |
CN113300426A (zh) * | 2021-04-27 | 2021-08-24 | 珠海迈巨微电子有限责任公司 | 功率器件、电池管理***及检测电路 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01227520A (ja) * | 1988-03-07 | 1989-09-11 | Nippon Denso Co Ltd | 電力用半導体装置 |
EP0402928A2 (en) * | 1989-06-16 | 1990-12-19 | National Semiconductor Corporation | Circuit for internal current limiting in a fast high side power switch |
JPH03143221A (ja) * | 1989-10-26 | 1991-06-18 | Fuji Electric Co Ltd | 過電流検出回路 |
JPH03262209A (ja) * | 1990-03-12 | 1991-11-21 | Nec Kansai Ltd | 電流検出回路 |
JPH04134271A (ja) * | 1990-09-27 | 1992-05-08 | Nec Corp | 出力回路 |
JP2000059982A (ja) * | 1998-08-05 | 2000-02-25 | Toyota Motor Corp | 過電流検出回路 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3887863A (en) * | 1973-11-28 | 1975-06-03 | Analog Devices Inc | Solid-state regulated voltage supply |
US4055812A (en) * | 1976-08-13 | 1977-10-25 | Rca Corporation | Current subtractor |
US4553084A (en) * | 1984-04-02 | 1985-11-12 | Motorola, Inc. | Current sensing circuit |
JPH0769749B2 (ja) * | 1990-10-25 | 1995-07-31 | 関西日本電気株式会社 | 直流電源回路 |
JPH05315852A (ja) * | 1992-05-12 | 1993-11-26 | Fuji Electric Co Ltd | 電流制限回路および電流制限回路用定電圧源 |
US5670829A (en) * | 1995-03-20 | 1997-09-23 | Motorola, Inc. | Precision current limit circuit |
JP3171129B2 (ja) * | 1996-11-01 | 2001-05-28 | 株式会社デンソー | 定電流制御機能を有する乗員保護装置の駆動回路および定電流制御回路 |
JPH10283040A (ja) * | 1997-04-08 | 1998-10-23 | Toshiba Corp | 電圧分圧回路、差動増幅回路および半導体集積回路装置 |
US6768623B1 (en) * | 2000-11-17 | 2004-07-27 | Texas Instruments Incorporated | IC excess current detection scheme |
-
2004
- 2004-05-18 JP JP2004147290A patent/JP2005333691A/ja active Pending
-
2005
- 2005-05-17 WO PCT/JP2005/008967 patent/WO2005112217A1/ja active Application Filing
- 2005-05-17 US US11/597,012 patent/US20070229041A1/en not_active Abandoned
- 2005-05-17 CN CNA2005800156131A patent/CN1954469A/zh active Pending
- 2005-05-17 KR KR1020067024162A patent/KR20070009712A/ko not_active Application Discontinuation
- 2005-05-18 TW TW094116121A patent/TW200540431A/zh unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01227520A (ja) * | 1988-03-07 | 1989-09-11 | Nippon Denso Co Ltd | 電力用半導体装置 |
EP0402928A2 (en) * | 1989-06-16 | 1990-12-19 | National Semiconductor Corporation | Circuit for internal current limiting in a fast high side power switch |
JPH03143221A (ja) * | 1989-10-26 | 1991-06-18 | Fuji Electric Co Ltd | 過電流検出回路 |
JPH03262209A (ja) * | 1990-03-12 | 1991-11-21 | Nec Kansai Ltd | 電流検出回路 |
JPH04134271A (ja) * | 1990-09-27 | 1992-05-08 | Nec Corp | 出力回路 |
JP2000059982A (ja) * | 1998-08-05 | 2000-02-25 | Toyota Motor Corp | 過電流検出回路 |
Also Published As
Publication number | Publication date |
---|---|
TW200540431A (en) | 2005-12-16 |
KR20070009712A (ko) | 2007-01-18 |
US20070229041A1 (en) | 2007-10-04 |
JP2005333691A (ja) | 2005-12-02 |
CN1954469A (zh) | 2007-04-25 |
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