JP2011254562A - Motor current detection ic, and current detector and motor controller using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a current detection circuit for a motor controller capable of realizing miniaturization, and reducing the number of components, the size of implementation, area and cost.SOLUTION: An IC internally includes a differential amplifier, a pair of +/- input terminals of the differential amplifier, and an output terminal of the differential amplifier. Miniaturization of a current detection circuit and cost reduction are executed so as to make a motor control circuit or a motor control device, and a various apparatus using the motor control device smaller, and to reduce cost by allowing an input of a negative voltage to the input terminals of the differential amplifier and integrating a circuit having the input terminals of the differential amplifier and a function to cut off the circuit when excessive voltage is inputted.

Description

  The present invention relates to a motor current detection IC which is a part of a motor control circuit, and a current detector or motor control device using the same.

  Conventionally, an inverter circuit has been widely used as a control device for a three-phase synchronous motor (hereinafter abbreviated as a motor generically) such as a three-phase induction motor or a brushless motor, and a motor winding is used as a part of the control circuit. Line current is being detected. There are roughly two methods for detecting the winding current of the motor.

  The first method is a method of directly detecting the current of the motor winding by using a current detector using a Hall sensor or the like in an electric path connected to the winding of the motor. In this method, the winding current of the motor can be detected with high accuracy, and when a sensor using a Hall element is used, insulation between the winding and the control circuit is possible. In general, a three-phase motor often uses two circuits. However, with this method, the detector (or detection circuit) is relatively large and expensive. Generally, it is used for a control device that requires high-precision control, such as a control circuit for an industrial servo motor.

  The second method is a method of amplifying the voltage drop by inserting a low resistance for current detection in series with the -power source side of the -side (lower) element of the inverter circuit. In this method, the current flowing through the low resistance for current detection changes with respect to the ON / OFF timing of each element of the inverter. Therefore, it is necessary to control the timing detected by the control circuit, and many use a microcomputer. Being controlled. In addition, since the potential of the signal to be detected is the negative potential of the inverter circuit, there is no problem when the control circuit is installed at the same potential. An isolation circuit is required. However, since this method allows a current detection circuit to be configured at a relatively low cost, it is widely used for controlling industrial three-phase induction motor driving inverters, motors for household appliances such as washing machines and air conditioners (for example, patent documents). 1).

  FIG. 9 is a block diagram of the motor driving device according to the first embodiment of the conventional example, and shows an example of a heat pump type washing / drying machine.

  In FIG. 9, a DC power source that converts AC power to DC power by applying AC power to a rectifier circuit 2 composed of a full-wave rectifier circuit 20 and an electrolytic capacitor 21 from the AC power source 1 is configured. The inverter circuit 3B and the third inverter circuit 3C convert DC power into three-phase AC power, and a rotary drum drive motor (first motor) 4A, a heat pump compressor motor (second motor) 4B, and The blower fan motor 4C is driven. The first current detection means 5A, the second current detection means 5B, the third current detection means 5C, which are connected to the emitter terminal of the lower arm switching transistor of each inverter circuit and detect the motor current, and the control means 6 The current of each of the rotary drum drive motor (first motor) 4A, the heat pump compressor motor (second motor) 4B, and the blower fan motor 4C is detected and controlled.

  The inverter control means 60 is a high-speed processor such as a microcomputer incorporating a plurality of PWM control means (not shown) for PWM-controlling the inverter circuits 3A, 3B, 3C and a high-speed A / D conversion means (not shown). The inverter circuits 3A, 3B, and 3C are simultaneously controlled, and the rotary drum drive motor 4A, the heat pump compressor motor 4B, and the blower fan motor 4C are controlled at different rotational speeds.

  The first inverter circuit 3A controls the rotary drum drive motor 4A. The position detection means 40a detects the position of the rotor permanent magnet, and the first current detection means 5A detects the motor current of the rotary drum drive motor 4A. Is detected, and the rotary drum drive motor 4A is controlled.

  The second inverter circuit 3B controls the heat pump compressor motor 4B, and the third inverter circuit 3C controls the blower fan motor 4C in the same manner as the first inverter circuit 3A.

  The current detection means 5A, 5B, and 5C are three shunt type current detection systems, and are composed of three or two shunt resistors and current signal amplification means. The basic configurations of the current detection means 5A, 5B, and 5C are exactly the same. Since the shunt resistance value varies depending on the motor current, a representative example will be described below. One terminal of the shunt resistor is connected to each emitter terminal (Nu, Nv, Nw) of the full-bridge three-phase inverter circuit lower arm transistor, and the other terminal of the shunt resistor is connected to the DC power source negative side G terminal. Each is composed of three shunt resistors, so it is called a three shunt method.

  FIG. 10 is a detailed circuit diagram of an inverter circuit in the conventional example, and an inverter circuit is constituted by a power module including six transistors, a diode, and a control IC. Here, one U-phase arm 30A of the three-phase arm will be described. A parallel connection body of an upper arm transistor 31a1 made of an insulated gate bipolar transistor (hereinafter abbreviated as IGBT) and an antiparallel diode 32a1, and a lower arm made of IGBT. The parallel connection body of the transistor 31a2 and the antiparallel diode 32a2 is connected in series, the collector terminal of the upper arm transistor 31a1 is connected to the positive potential terminal P1 of the DC power supply, and the emitter terminal of the upper arm transistor 31a1 is the output to the motor 4 The emitter terminal Nu of the lower arm transistor 31a2 is connected to the negative potential side terminal G1 of the high-voltage DC power source via the U-phase shunt resistor 50a constituting the current detecting means 5.

  The upper arm transistor 31a1 is driven by the upper arm gate drive circuit 33a1 in accordance with the upper arm drive signal Up, and the lower arm transistor 31a2 is subjected to on / off switching control by the lower arm gate drive circuit 33a2 in accordance with the lower arm drive signal Un.

  The V-phase arm 30B and the W-phase arm 30C are similarly connected, and the emitter terminals Nv and Nw of the lower arm transistor of each arm are connected to the V-phase shunt resistor 50b and the W-phase shunt resistor 50c constituting the current detecting means 5. The other terminals of the V-phase shunt resistor 50b and the W-phase shunt resistor 50c are connected to the DC power source negative potential terminal G1. If the lower arm transistor is constituted by an IGBT or a power MOSFET, switching can be controlled by controlling the gate voltage. Therefore, the voltage of the shunt resistor connected to the emitter terminal in the case of IGBT and the source terminal in the case of power MOSFET is 1V or less. If the resistance value is selected, the on / off switching control can be performed by voltage control with almost no effect on the switching operation, and the inverter can be detected by detecting the voltages veu, vev, and vew of the UVW phase shunt resistors 50a, 50b, and 50c. The circuit output current, that is, the motor current can be detected.

  FIG. 11 is a detailed circuit diagram in which the current signal amplifying means of the current detecting means 5 according to the prior art is constituted by a single power source amplifying circuit, and the AC current signals detected by the UVW phase shunt resistors 50a, 50b, 50c are non-inverted. The signal is converted and amplified by an amplifier, and level-converted to a DC voltage level that can be detected by an A / D converter incorporated in a processor such as a microcomputer.

JP 2008-054812 A

  However, such a conventional motor current detection circuit conventionally determines a shunt resistor that detects a motor current as a voltage, an amplifier constituting an amplifier (generally an operational amplifier is used), and the gain of the amplifier. It is composed of a plurality of resistors and other components such as capacitors and diodes, which requires a large number of components, requires a large mounting area, and is costly. In addition, although the prior art describes the modularization of the current detection circuit, the shunt resistor, the amplifier constituting the amplifier, a plurality of resistors, and components such as a capacitor and a diode are combined as a module such as a hybrid IC. However, there is a limit to what can be reduced to some extent, and in terms of cost, it is never cheaper by modularization.

  The reason why the current detection circuit is configured by combining the individual components as described above is as follows.

  The first reason is that since the motor current flows in both positive and negative polarities, a positive and negative voltage also flows through the shunt resistor that detects the motor current of the motor current detection circuit. As a result, a positive voltage is applied across the shunt resistor. A negative voltage is generated. In general, a voltage within the range of positive and negative power supply voltages is usually input to the input terminal of the amplifier constituting the amplifier. In order to connect the voltage generated by the shunt resistor to the amplifier connected to the shunt resistor, an amplifier of both positive and negative power supplies is used as the amplifier to be used, or a negative voltage generated by the shunt resistor is not applied to the amplifier. It was necessary to have a circuit configuration.

  The second reason is that there is a possibility that a high voltage for driving the motor may be applied to the amplifier when the shunt resistor for detecting the motor current is open or the like is abnormal. Excessive voltage may be applied, and the resin mold of the amplifier may rupture, causing ignition, smoke, etc. Of the resistors that make up the gain of the amplifier, the resistor connected between the shunt resistor and the amplifier works to suppress the current that flows into the amplifier in the event of an abnormality, and in some cases, the damage is minimized by fusing did it.

  For this reason, the conventional current detection circuit has a large number of components, requires a large mounting area, is expensive, and becomes more expensive in terms of cost when modularized and downsized.

  An object of the present invention is to solve the above-described conventional problems, and to reduce the size, reduce the number of parts, and reduce the cost in a current detection circuit that constitutes a part of a motor control circuit.

  In order to achieve the above object, the present invention comprises a differential amplifier circuit, a comparison circuit, a pair of + and − input terminals of the differential amplifier circuit, and an output terminal of the differential amplifier circuit. The input terminal of the amplifier circuit can input a negative voltage, the input terminal of the differential amplifier circuit has a function of cutting off the circuit of the terminal to which the excessive voltage is input when the excessive voltage is input, Motor current detection IC that compares the voltage input to any of the input terminals on the + side and-side of the differential amplifier circuit with the voltage determined by the detection value setting resistor connected to the outside and outputs the result. It is.

  As a result, the current detection circuit can be downsized, the number of parts is small, the mounting area is small, and the cost can be reduced.

  The motor current detection IC of the present invention is used to reduce the size and cost of the current detection circuit used in the motor control circuit, and uses a motor control circuit, a motor control device, or a motor control device. It is possible to reduce the size and cost of various devices.

Block diagram of motor control device using IC of the present invention Another block diagram of the motor control device using the IC of the present invention IC internal block diagram of the present invention Other IC internal block diagram of the present invention The figure which shows the surge protection element arrangement | positioning of IC input terminal of this invention The other figure which shows the surge protection element arrangement | positioning of IC input terminal of this invention IC internal structure diagram of the present invention The figure which shows the aluminum wiring of the IC input terminal vicinity of this invention Block diagram of a conventional motor drive device Detailed circuit diagram of inverter circuit of conventional motor drive device Detailed circuit diagram of single power amplifier circuit of current signal amplifying means of conventional motor driving device Another block diagram of the motor control device using the IC of the present invention Another block diagram of a motor control device using the IC of the present invention

  A first invention includes a differential amplifier circuit, a comparison circuit, a pair of + and − input terminals of the differential amplifier circuit, and an output terminal of the differential amplifier circuit, and an input terminal of the differential amplifier circuit Can input a negative voltage, and the input terminal of the differential amplifier circuit has a function of cutting off a circuit of a terminal to which an excessive voltage is input when an excessive voltage is input. By comparing the voltage input to either the + side or-side input terminal with the voltage determined by the detection value setting resistor connected to the outside, the result is output, and the circuit is integrated into an IC. By connecting the power source side of the lower switching element of the inverter circuit to be driven at once and connecting both ends of the low resistance inserted in series to the + and − pair of input terminals of the differential amplifier circuit, 1 Shunt-type current detection circuit and overcurrent detection circuit Can be configured, thereby as a current detection circuit, miniaturization, reduced number of parts, mounting area is small, it is possible to realize a cost reduction.

  The second invention comprises a plurality of sets of differential amplifier circuits, comparison circuits, a pair of + and − input terminals of the differential amplifier circuits, and output terminals of the differential amplifier circuits, and the differential amplifier circuit The input terminal of the differential amplifier circuit can input a negative voltage, and the input terminal of the differential amplifier circuit has a function of cutting off a circuit of a terminal to which an excessive voltage is input when an excessive voltage is input, and the input of the plurality of comparison circuits One end of each of the differential amplifiers is connected to one of the input terminals of the positive side and the negative side, and the other ends of the inputs of the plurality of comparison circuits are connected together and connected to the outside for detection value setting When a voltage determined by a resistor is input, a plurality of outputs of the comparison circuit are output as a single output, and the result is output as an IC. Each of the lower side of the driving inverter circuit A three-shunt current detection circuit is formed by individually inserting low resistances in series on the negative side of the switching element and connecting both ends of the resistances to a pair of positive and negative input terminals of the differential amplifier circuit, respectively. As a result, the current detection circuit can be downsized, the number of components is small, the mounting area is small, and the cost can be reduced.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the gain of the differential amplifier circuit is provided with a function that can be adjusted from the outside, and the gain setting terminal is provided. A wide range of current detection values can be handled in combination with a low resistance for current detection installed outside.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, the power supply voltage is a single voltage. For example, the power supply voltage of the IC is a single power supply voltage of 5 V, so It is possible to operate with a common power source with other control circuits such as a microcomputer.

  In a fifth aspect based on any one of the first to fourth aspects, the surge protection element disposed at the + and − input terminals of the differential amplifier circuit is disposed between the positive side of the power supply voltage. In other words, a negative voltage is applied to the input terminal of the differential amplifier circuit by placing a surge protection element between the positive side of the IC power supply voltage in the vicinity of the wire bonding pad of the input terminal of the differential amplifier circuit. In this case, leak current does not flow through the surge protection element, and by applying a negative voltage, even when the motor current becomes negative, the current can be detected accurately without destruction of the IC. Can do.

  According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, two surge protection elements disposed at the + and − input terminals of the differential amplifier circuit are provided between the negative side of the power supply voltage. Are arranged in series with the polarity reversed, that is, two surge protection elements are placed between the negative side of the IC power supply voltage in the vicinity of the wire bonding pad of the input terminal of the differential amplifier circuit. By disposing the polarity in reverse, even if a negative voltage is applied to the input terminal of the differential amplifier circuit, no leakage current flows through the surge protection element, and by applying a negative voltage, the motor can be applied. Even when the current becomes negative, an accurate current can be detected without destroying the IC.

  In a seventh aspect based on any one of the first to fourth aspects, the + and − input terminals of the differential amplifier circuit blow off the wire bonding between the lead frame of the input terminal and the silicon chip when an excessive voltage is input. In other words, by using as thin a wire bonding as possible between the lead frame forming the IC pin of the input terminal of the differential amplifier circuit and the bonding pad on the same chip, for example, connecting to the outside of the IC When the detected low resistance for current detection becomes open, if the large current flows from the terminal connected to the low resistance switching element side, the wire bonding is blown to prevent the IC from bursting, firing, etc. Safety can be prevented.

  In an eighth invention according to any one of the first to fourth inventions, the + and − input terminals of the differential amplifier circuit are fused near the bonding pad of the aluminum wiring on the silicon chip when an excessive voltage is input. In other words, the aluminum wiring between the bonding pad on the same chip connected via wire bonding from the lead frame forming the IC pin of the input terminal of the differential amplifier circuit and the other circuit including the surge protection element By providing a thin part as much as possible, for example, when a low resistance for current detection connected to the outside of the IC is opened, a large current flows from a terminal connected to the low resistance switching element side. Further, by fusing the thinned portion of the aluminum wiring, it is possible to prevent unsafeities such as IC rupture and ignition.

  According to a ninth aspect of the present invention, there is provided a motor current detector comprising a motor current detection IC according to any one of the first to eighth aspects of the invention and a resistor connected between the + and-input terminals of the differential amplifier circuit of the IC. With this configuration, the motor current detector can be configured with one IC and a few components with low resistance, and can be downsized, have a small number of components, have a small mounting area, and can achieve cost reduction.

  A tenth aspect of the invention realizes a small and inexpensive motor control device by configuring a motor control device using a current detection circuit including the motor current detection IC of any one of the first to eighth aspects of the invention. can do.

  In an eleventh aspect of the invention, the motor current detection IC of the first to eighth aspects of the invention and a resistor connected to one of the + and-input terminals of the differential amplifier circuit via a protective element, By configuring the motor current detector, it can be configured as a motor current detector with one IC and a few parts with low resistance, and an element is connected to either + or-of the above-mentioned operation amplification circuit. For example, when a low resistance for current detection connected to the outside of the IC is opened by connecting a low resistance, a large current flows from a terminal connected to the low resistance switching element side. The protection element can prevent unsafeities such as IC rupture and ignition, and it can be reduced in size, has a small number of parts, has a small mounting area, is low in cost, and can constitute a highly safe current detector.

  According to a twelfth aspect of the present invention, the protection element according to the eleventh aspect of the present invention uses a fuse that cuts off the current. For example, when the low resistance for current detection connected to the outside of the IC is opened, the low resistance When a large current flows from the terminal connected to the switching element side of this, this fuse blows, preventing unsafe conditions such as IC rupture and fire, miniaturization, fewer parts, small mounting area, low A current detector with high cost and high safety can be configured.

  According to a thirteenth aspect of the present invention, when the protective element of the eleventh aspect of the present invention uses a resistor, for example, when a low resistance for current detection connected to the outside of the IC is opened, the low resistance switching element side When a large current flows from the terminal connected to the IC, this resistance can be blown to prevent unsafe conditions such as IC rupture and fire, miniaturization, small number of parts, small mounting area, low cost, and safety A highly efficient current detector can be configured.

  In the fourteenth invention, a small and inexpensive motor control device can be realized by configuring the motor control device using the motor current detector of the eleventh to thirteenth inventions.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the thing of the same structure as a prior art example attaches | subjects the same code | symbol, and abbreviate | omits description. Further, the present invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a block diagram of a motor control apparatus using the IC of the present invention, and FIG. 3 is a block diagram of the IC of Embodiment 1 of the present invention.

  In FIG. 1, the inverter circuit for driving a three-phase motor is composed of two switching elements 31a1 and 31a2, 31b1 and 31b2, 31c1 and 31c2 connected in series, three sets in parallel, a total of six switching elements. In FIG. 1, an IGBT is used as a switching element as an example. A connection point of a set of two switching elements, for example, the lower side (emitter side) of 31a1 and the upper side (collector side) of 31a2 are connected, and the connection point is connected to a motor (not shown). The emitter sides of the lower switching elements connected in series are all connected and connected to a current detection low resistance 50d, which is a current detection resistance. Both ends of the current detection low resistance 50d are input to the motor current detection IC 101. The motor current detection IC 101 amplifies the voltage at both ends of the current detection low resistance 50d by the differential amplifier circuit 105 and outputs it as an analog signal idc. This signal is input to a control circuit 102 such as a microcomputer, performs A / D conversion, and is used as a detected current value for motor speed control, torque control, and the like.

In FIG. 3, both ends of the aforementioned current detection low resistance 50d are connected to input terminals T1 and T2. For the sake of explanation, the input terminal T1 is connected to the right side of the current detection low resistance 50d shown in FIG. 1 and the emitter side of the lower IGBT, and the input terminal T2 is connected to the left side of the current detection low resistance 50d shown in FIG. Assume that the C1 side is connected. The input voltage to the input terminal T1 is V _T1 [V], the input voltage to the input terminal T2 is V _T2 [V], the output voltage to the output terminal T7 is V _OUT [V], and the _VREF side of the resistor R4 in FIG. _Is V _REF [v], and the resistance values of resistors R1, R2, R4, and R5 are R ₁ [Ω], R ₂ [Ω], R ₄ [Ω], and R ₅ [Ω], the output voltage is ,

V _OUT = {(R ₁ R ₂ + R ₁ R ₅ ) V _REF + (R ₂ R ₄ + R ₄ R ₅ ) V _T1
+ (− R ₁ R ₅ −R ₄ R ₅ ) V _T2 } / {R ₂ (R ₁ + R ₄ )}

It is represented by In general, when configuring a differential amplifier circuit, the values of the resistors R1, R2, R4, and R5 are R ₁ = R ₂ and R ₄ = R ₅ (or R1: R4 = R2: R5), If you assign this to an expression,

V _OUT = V _REF + (V _T1 −V _T2 ) R ₄ / R ₁

Thus, the voltage V _REF is set as the virtual GND, and the voltage amplified with the amplification factor R ₄ / R ₁ is connected to the terminal T7 with the voltage V _REF as the center.

The example of the design value of each constant is shown. Now, the maximum value of the motor current is set to ± 8 A (zero-peak). The voltage drop due to the current detection low resistance 50d should be 1 V or less so that the current detection low resistance 50d shown in FIG. 1 does not affect the operation of the IGBTs 31a2, 31b2, 31c2 constituting the inverter. When the value of the low resistance is 50 mΩ, the voltage drop due to the maximum current of the motor is 8 A × 50 mΩ = 0.4 V, and even if it exceeds 8 A, the inverter circuit elements can be driven with a margin. Assuming that the control circuit 102 shown in FIG. 1 is an A / D converter of a microcomputer, a voltage that can be input is generally 0 V to 5 V, and a range of ± 2.5 V with reference to 2.5 V of the center voltage. I want to set the voltage of the differential amplifier. In this case, the reference voltage V _REF inside the IC is set to 2.5V. The resistors R6 and R7 are set so that the reference voltage VREF composed of the resistors R6 and R7 and the amplifier 112 shown in FIG. For example, when the power supply voltage VCC of the IC is + 5V, the values of the resistors R6 and R7 are set equal. A voltage of 0.4 V is input between the input terminals T1 and T2 when the maximum motor current is 8A. The amplitude at this time needs to be 2.5 V or less. For example, if the resistors in FIG. 3 are set to R ₁ = R ₂ = 40 kΩ and R ₄ = R ₅ = 200 kΩ, the amplification factor of the amplifier is 200 kΩ / 40 kΩ = 5 times, and the amplitude of the output terminal T7 at the maximum current of 8 A is 0. 4V × 5 = 2.0V.

  In FIG. 1, the IC 101 also outputs a detection signal of the set current level. The input terminal T1 is connected to one input terminal of a comparator (comparison circuit) 111 through a low pie filter composed of a resistor R3 and a capacitor C1. The other input terminal of the comparator 111 receives a voltage determined by a current source 114 and a resistor (not shown) connected between the detection value setting terminal T10 and the circuit GND. As in the description in the first embodiment, the current detection low resistance 50d for current detection in FIG. 1 is 50 mΩ, the maximum value of the motor current is 8A, and a signal is obtained by current detection in a circuit including the comparator 111. Suppose that the desired level is 9A. A constant is set to invert the comparator output at 50 mΩ × 9A = 0.45V. If the current source 114 is 100 μA, a resistance of 0.45 V ÷ 100 μA = 4.5 kΩ may be connected between the detection value setting terminal T10 and the circuit GND. Further, since the current detection signal output to the terminal T7 is used for motor control and is not easily affected by noise or the like, the differential amplifier circuit 105 including the amplifier 110 and the surrounding resistors has a low resistance for current detection. This is because the current waveform is faithfully detected. Since the current detection in the circuit including the comparator 111 is intended to detect the current level, the noise component is removed by the resistor R3 and the capacitor C11 without being differential. The values of R3 and C11 are such that R3 is 40 kΩ, C11 is 50 pF, and the capacitor value is within a range that can be configured inside the IC, and the time constant is 2 μsec.

  In the configuration shown in FIG. 3, when the right side of the current detection low resistance 50 d in FIG. 1, that is, the IGBT side is connected to the input terminal T <b> 1 side, the comparator 111 has a resistance value whose current value is connected to the detection value setting terminal T <b> 10. Output terminal T11 outputs L, and T12 outputs H. This detection signal can be used as an overcurrent detection signal, and can be used for protection of inverter switching elements, short-circuit protection of motor windings, and the like.

  As shown in FIG. 1, the circuit ground GND of the control circuit and the detection circuit is generally the left side of the current detection low resistance 50d for current detection and the side not connected to the switching element. When the motor current is negative, current may flow from the left side to the right side of FIG. 1 through the current detection low resistance 50d for current detection. In that case, a negative voltage is input to the input terminal T1 in the block diagram of FIG. 3IC. In the present invention, the input terminal T1 to which the negative voltage of the IC may be applied is configured to have a higher tolerance for the negative voltage.

  Further, when the current detection low resistance 50d for current detection becomes open due to burnout or solder removal, a high voltage of the inverter circuit is applied to the right side of the current detection low resistance 50d in FIG. 1, that is, the IGBT side. There is a possibility. At this time, an excessive voltage may be applied to the input terminal T1 in the block diagram of FIG. 3IC. In the present invention, the terminal T1 to which an excessive voltage of the IC may be applied has a function of interrupting a current inflow path when an excessive voltage is applied and a large current flows, leading to rupture, ignition, etc. of the resin package. It has no configuration.

  Each of the above constants is an example, and the value varies depending on conditions such as a motor current value and an output voltage to the control circuit. Further, the internal block configuration of the IC is only an example, and for example, the input terminals T1 and T2 and the input polarity to the differential amplifier, or the configuration of the differential amplifier may be different.

(Embodiment 2)
FIG. 2 is a block diagram of a motor control device using the IC of the present invention, and FIG. 4 is a block diagram of the IC of Embodiment 2 of the present invention.

  Hereinafter, the difference from Embodiment 1 will be mainly described. The description of the same configuration as that in Embodiment 1 is omitted.

  In FIG. 2, the inverter circuit for driving a three-phase motor is composed of three switching elements 31a1 and 31a2, 31b1 and 31b2, 31c1 and 31c2 connected in series, three sets in parallel, for a total of six switching elements. In FIG. 2, an IGBT is used as a switching element as an example. A connection point of a set of two switching elements, for example, the lower side (emitter side) of 31a1 and the upper side (collector side) of 31a2 are connected, and the connection point is connected to a motor (not shown). Low current resistors 50a, 50b, 50c, which are current detection resistors, are individually connected to the emitter side of each lower switching element connected in series, and the other end of each low resistance is connected to an inverter power source. Is connected to the negative side of Both ends of each current detection low resistance are input to the motor current detection IC 103. That is, the IGBT side of the current detection low resistance 50a in FIG. 2 is at the input terminal T1 in FIG. 4, the other end of the current detection low resistance 50a is at the input terminal T2, and the IGBT side of the current detection low resistance 50b in FIG. 4 is connected to the input terminal T3 in FIG. 4, the other end of the current detection low resistance 50b is connected to the input terminal T4, and the IGBT side of the current detection low resistance 50c is connected to the input terminal T5 in FIG. The other end of 50c is connected to the input terminal T6. The motor current detection IC 103 amplifies the voltages at both ends of the current detection low resistances 50a, 50b, and 50c, and outputs them as analog signals iu, iv, and iw. This signal is input to a control circuit 104 such as a microcomputer, performs A / D conversion, and is used as a detected current value for motor speed control, torque control, and the like.

  The difference from the first embodiment is that the first embodiment collectively detects the current for three phases, while the second embodiment can detect each phase independently. For this reason, it can be used when more accurate control is required. Since the explanation of each constant is the same as that of the first embodiment, it will be omitted.

  The input terminals T1, T3, and T5 are connected to one input terminal of each of the three comparators through a low pie filter including a resistor R3 and a capacitor C1. The other input terminals of the comparators are connected together, and a common voltage is input that is determined by a current source 114 and a resistor (not shown) connected between the detection value setting terminal T10 and the circuit GND. The outputs of the three comparators are also common. When one of the comparators reaches a voltage determined by a resistor (not shown) connected between the detection value setting terminal T10 and the circuit GND, a signal is output from the terminals T9 and T10. Is output. This detection signal can be used as an overcurrent detection signal, and can be used for protection of inverter switching elements, short-circuit protection of motor windings, and the like. The method for setting each constant is the same as that in the first embodiment, and will be omitted.

  Further, the negative voltage resistance, overcurrent resistance, and the like are the same as those in the first embodiment, and are omitted.

(Embodiment 3)
In the first embodiment or the second embodiment, a function for adjusting or selecting the amplification factor of the differential amplifier circuit 105 is provided, and a setting terminal for the amplification factor is provided. An example will be described with reference to FIGS. 3 and 4, terminals T <b> 13 and T <b> 14 are gain setting terminals and are input to the gain setting unit 113. In the example of FIGS. 3 and 4, since there are two terminals T13 and T14, four types of states can be set. The amplification factor setter 113 changes the values of the resistors R4 and R5 depending on the state of the terminals T13 and T14, for example. Now, as described in the first embodiment, it is assumed that the resistors R1 and R2 are 40 kΩ. The amplification factor setter 113 simultaneously sets R4 and R5 to 100 kΩ, 200 kΩ, 400 kΩ, and 800 kΩ depending on the states of the terminals T13 and T14. The amplification factors are 2.5 times, 5 times, 10 times, and 20 times, respectively.

  Accordingly, when the current value of the motor to be controlled is small, for example, when the current is 1 A or less at the maximum, the current detection low resistance 50d for current detection shown in FIG. 1 and the current detection resistors 50a, 50b and 50c shown in FIG. By setting the value to 1Ω and the current amplification factor to 2.5 times, it is possible to detect a current with an excellent S / N ratio although the current is small. Also, when the current is large, the loss of the current detection resistor increases, so it is desirable to reduce the resistance value as much as possible. For example, when the maximum value of the current detection value is 20 A, the current detection low resistance 50d for current detection shown in FIG. 1, the values of 50a, 50b, and 50c shown in FIG. 3 are 10 mΩ, and the current amplification factor is 20 times. Thus, it is possible to configure a current detection circuit that suppresses loss due to resistance as much as possible.

  Although the description has been given assuming that the setting of the amplification factor is four types using two terminals, the number of amplification factor setting terminals may be other than the two terminals. For example, the amplification factor setting terminal can be set to only one terminal, and the amplification factor of the differential amplifier circuit can be set in two stages such as 5 times and 10 times. Further, the amplification factor setting terminals can be set to three terminals, and the amplification factors of five or more types of differential amplifier circuits can be set. Further, the amplification factor may be set in an analog manner. For example, by connecting a resistor between the terminal and the circuit GND at one terminal and using an analog input, the resistors R4 and R5 can be set linearly using a current mirror inside the amplification factor setting unit.

(Embodiment 4)
In any of the first to third embodiments, the power supply voltage of the IC is, for example, a single power supply voltage of 5V.

  An example will be described with reference to FIGS. 3 and 4, the power supply terminal T15 is connected to the + side power supply input terminal, and the IC internal power supply VCC is connected to the power supply terminal T15. The ground terminal T16 is connected to the ground terminal and IC internal ground GND. As described in the first to fourth embodiments, the IC of the present invention can input a negative voltage to the input terminal, and the power source of the IC can be a single power source of + 5V. As a result, the power source can be shared with the microcomputer and the logic circuit constituting the control circuit, a dedicated power source unique to the analog circuit is unnecessary, and the current detection circuit and the motor control circuit can be downsized.

(Embodiment 5)
In any of the first to fourth embodiments, a surge protection element is disposed between the positive side of the power supply voltage of the IC in the vicinity of the wire bonding pad of the input terminal of the differential amplifier circuit.

  FIG. 5 shows an embodiment thereof. The terminal T is a terminal to which a negative voltage is applied, and the IC internal power supply VCC is supplied from the outside through the power supply terminal T15. The IC internal ground GND is connected to an external circuit ground via a ground terminal T16. The surge protection element 120 is connected between the input terminal T and the IC internal power supply VCC as shown in the figure. The characteristics of the surge protection element are similar to those of a Zener diode. The withstand voltage of the surge protection element is sufficiently higher than the power supply voltage. For example, when the power supply voltage of the IC is 5V, the breakdown voltage of the surge protection element needs to be at least about 7V.

  When a positive voltage surge is applied to the terminal T, the surge protection device 120 exhibits a forward voltage characteristic of the Zener diode, and clamps the surge at a value obtained by adding the forward voltage of the Zener diode to the power supply voltage of the IC. If the IC power supply voltage is + 5V, the surge on the positive voltage side is clamped at about + 5.7V.

  When a negative voltage surge is applied to the terminal T, the surge protection device 120 clamps the surge voltage with a value obtained by subtracting the Zener voltage of the Zener diode from the power supply voltage of the IC. Assuming that the power supply voltage of the IC is + 5V and the withstand voltage of the surge protection element is 7V, the surge on the negative voltage side is clamped at -2V.

  As a result, even when a negative voltage is applied to the input terminal of the differential amplifier circuit, no leakage current flows through the surge protection element, and the negative current can be applied, thereby making the motor current negative. In addition, an accurate current can be detected without destroying the IC.

(Embodiment 6)
In any one of the first to fourth embodiments, two surge protection elements are connected in series between the internal ground of the IC in the vicinity of the wire bonding pad of the input terminal of the differential amplifier circuit, with the polarity reversed. Then place. Even when a negative voltage is applied to the input terminal of the differential amplifier circuit, no leakage current flows through the surge protection element, and by applying a negative voltage, the IC can be applied even when the motor current becomes negative. It is possible to detect an accurate current without destroying.

  FIG. 6 shows an embodiment thereof. The terminal T is a terminal to which a negative voltage is applied, and the IC internal power supply VCC is supplied from the outside through the power supply terminal T15. The IC internal ground GND is connected to an external circuit ground via a ground terminal T16. The surge protection elements 121 and 122 are connected between the input terminal T and the IC internal power supply VCC in series in reverse polarity as shown in the figure. The characteristics of the surge protection element are similar to those of a Zener diode. The surge protection element 121 needs to have a breakdown voltage of about 2 V or more, and the surge protection element 122 needs a value sufficiently higher than the power supply voltage of the IC.

  When a positive voltage surge is applied to the terminal T, the surge protection element 121 shows the forward voltage characteristic of the Zener diode, and the surge protection element 122 shows the Zener voltage characteristic of the Zener diode. The surge is clamped at the value obtained by adding these voltages. When the IC power supply voltage is + 5V and the withstand voltage of the surge protection element 122 is 7V, the positive voltage side surge is clamped at about + 7.7V.

  When a negative voltage surge is applied to the terminal T, the surge protection element 121 shows the Zener voltage characteristic of the Zener diode, and the surge protection element 122 shows the forward voltage characteristic of the Zener diode. If the withstand voltage of the surge protection element 121 is 2V, the surge on the negative voltage side is clamped at -2.7V.

  As a result, even when a negative voltage is applied to the input terminal of the differential amplifier circuit, no leakage current flows through the surge protection element, and the negative current can be applied, thereby making the motor current negative. In addition, an accurate current can be detected without destroying the IC.

(Embodiment 7)
In any one of the first to fourth embodiments, the wire bonding used between the lead frame forming the IC pin of the input terminal of the differential amplifier circuit and the bonding pad on the same chip is used as much as possible. .

  FIG. 7 shows the structure of the IC. The terminal 152 and the base substrate 153 are formed by punching a lead frame. In general, the base substrate 153 is common to any one of the plurality of terminals 152 constituting the IC. The chip 154 is bonded to the base substrate 153 with silver paste or the like. The wire bonding 155 electrically connects the lead frame 152 and the bonding pad on the chip 154. The resin mold 151 protects the IC chip and wires and fixes the lead frame.

  When the current detection low resistance 50d for current detection shown in FIG. 1 and the current detection low resistances 50a, 50b, 50c shown in FIG. 2 are opened due to burnout or solder removal, the low resistance IGBT The high voltage of the inverter circuit may be applied to the side. At this time, an excessive voltage may be applied to the input terminal T1 in the block diagrams of the ICs in FIGS. At this time, the current flows through the wire bonding 155 as a current flowing path, and the current flows through the surge protection element shown in the seventh and eighth embodiments. Use as thin a wire as possible for this wire bonding.

  Thus, for example, when a low resistance for current detection connected to the outside of the IC is opened, the wire bonding is blown when a large current flows from a terminal connected to the low resistance switching element side. Can prevent unsafe conditions such as IC rupture and fire.

(Embodiment 8)
In any one of the first to fourth embodiments, a bonding pad and a surge protection element on the same chip are connected via wire bonding from a lead frame forming an IC pin of an input terminal of the differential amplifier circuit. A thin part as much as possible is provided in the part of the aluminum wiring between other circuits including.

  FIG. 8 shows the structure near the bonding pad of the IC. Aluminum wiring is provided on the surface of the IC chip 201. The aluminum wiring 202 in the vicinity of the bonding pad 203 is generally directly connected to the surge protection element 204 installed in the vicinity of the bonding pad. Each signal passes through the surge protection element, for example, through the contact hole 205, or is routed into the IC through aluminum wiring on the surface layer. FIG. 8A shows an example of aluminum wiring in the vicinity of a bonding pad that is generally performed.

  The aluminum wiring near the bonding pad of the present invention is shown in FIG. A thin portion is provided in the aluminum wiring between the bonding pad 203 and the surge protection element 204. Each signal passes through the surge protection element, for example, through the contact hole 205, or is routed into the IC through aluminum wiring on the surface layer.

  When the current detection low resistance 50d for current detection shown in FIG. 1 and the current detection low resistances 50a, 50b, 50c shown in FIG. 2 are opened due to burnout or solder removal, the low resistance IGBT The high voltage of the inverter circuit may be applied to the side. At this time, an excessive voltage may be applied to the input terminal T1 in the block diagrams of the ICs in FIGS. At this time, the current flows through the bonding pad 203 as a current flow path, and the current flows through the surge protection element 204 shown in the seventh and eighth embodiments. Make a thin part from the bonding pad to the aluminum wiring of the surge protection element.

  As a result, for example, when a low resistance for current detection connected to the outside of the IC is opened, the aluminum wiring becomes thin when a large current flows from a terminal connected to the low resistance switching element side. By fusing the part, it is possible to prevent unsafe conditions such as IC rupture and ignition.

(Embodiment 9)
The current detector includes the current detection IC shown in any one of the first to eighth embodiments and a low resistance for current detection connected to an input terminal.

  1 and 2 are block diagrams of the motor control device.

  In the motor control device configuration of FIG. 1, an inverter circuit is configured by six IGBTs 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2. The lower three IGBTs 31a2, 31b2, and 31c2 are connected at their emitter terminals, which are power supply side terminals, connected to the current detection low resistance 50d, and connected at the other end to the negative side of the capacitor 108. Has been. In general, a rectifier circuit of a commercial AC power supply (not shown) is connected to both ends of the capacitor 108 and to the left side in FIG. 1, for example, a double voltage rectifier circuit of a single-phase AC 100V or a single-phase or three-phase AC 200V all. When a wave rectifier circuit is connected, a DC voltage of about 280 V is applied to the voltage across the capacitor 108. The current detector 106 includes the current detection low resistance 50d for current detection and the current detection IC 101. Both ends of the current detection low resistance are connected to terminals T1 and T2 in the block diagram of the current detection IC shown in FIG. Terminals T <b> 1 and T <b> 2 are inputs to the amplifier circuit 105 inside the current detection IC 101. Since the detailed description of the IC has already been described above, it will be omitted.

  Next, the motor control device configuration in FIG. 2 will be described. The six IGBTs 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 constitute an inverter circuit. The current detection low resistances 50a, 50b, and 50c are separately connected to the emitter terminals that are the negative power supply side terminals of the three lower IGBTs 31a2, 31b2, and 31c2. That is, one end of the current detection low resistance 50a is connected to the emitter side of the IGBT 31a2, one end of the current detection low resistance 50b is connected to the emitter side of the IGBT 31b2, and one end of the current detection low resistance 50c is connected to the emitter side of the IGBT 31c2. The other ends of the current detection low resistances 50a, 50b, and 50c are connected to the negative side of the capacitor 108. In general, a rectifier circuit of a commercial AC power source (not shown) is connected to both ends of the capacitor 108 and to the left side in FIG. 2, for example, a double voltage rectifier circuit of a single-phase AC 100V or a single-phase or three-phase AC 200V all. When a wave rectifier circuit is connected, a DC voltage of about 280 V is applied across the capacitor 108. The current detector 107 includes the current detection low resistances 50a, 50b, and 50c for current detection and the current detection IC 103. Both ends of the current detection low resistance are shown in FIG. 4 such that both ends of the current detection low resistance 50a are terminals T1 and T2 in the block diagram of the current detection IC 103 shown in FIG. 4, and both ends of the current detection low resistance 50b are shown in FIG. Both ends of the current detection low resistance 50c are connected to terminals T5 and T6 of the current detection IC 103 shown in FIG. 4, respectively, to the terminals T3 and T4 of the current detection IC 103. Each terminal is an input of the differential amplifier circuit 105 inside the current detection IC 103. Since the detailed description of the IC has already been described above, it will be omitted.

(Embodiment 10)
A motor control device using a current detection circuit including the current detection IC described in any of the first to eighth embodiments.

  1 and 2 are block diagrams of the motor control device. Since the contents of IC internal configuration, operation, and current detection have already been described, they will be omitted.

  The control circuit 102 in FIG. 1 is mainly configured by a microcomputer (not shown), for example, and the current detection signal idc is connected to the A / D conversion port of the microcomputer. The microcomputer controls the gate signals of the switching elements 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 constituting the inverter and drives the motor. For example, when the switching elements 31a1, 31b1, and 31c2 are on and the other three elements are off, the current detection is connected to the switching elements 31c1 and 31c2 via the current detection low resistance 50d and the IC. It is possible to detect the current of the motor winding, which is the current from the motor winding in the circuit direction of the inverter. For example, when the switching elements 31a1, 31b2, and 31c2 are on and the other three elements are off, they are connected to the switching elements 31a1 and 31a2 via the current detection low resistance 50d and the IC. The motor winding current can be detected from the inverter circuit in the direction of the motor winding.

  The control circuit 102 controls the motor using the motor winding current thus obtained and information of other detectors (not shown) such as a position sensor, a speed sensor, and a power supply voltage sensor attached to the motor. The detection signal OC is normally used as an overcurrent detection signal. When this signal is detected, the control circuit 102 immediately cuts off the gate signals of the switching elements 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 of the inverter to prevent the destruction of the switching elements.

  In this way, it is advantageous in terms of cost if the current detection resistor as shown in FIG. 1 is performed at only one place, but the control circuit determines which current is detected depending on the operation of the inverter circuit and the direction of the current. Need to judge. Such a configuration is often used in a relatively simple motor control device such as a fan motor control.

  The control circuit 104 in FIG. 2 is configured mainly with a microcomputer (not shown), for example, and the current detection signals iu, iv, and iw are connected to an A / D conversion port of the microcomputer. The microcomputer controls the gate signals of the switching elements 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 constituting the inverter and drives the motor. For example, when the switching elements 31a2, 31b2, and 31c2 on the lower side of the inverter circuit are on and the other three are off, the current detection low resistances 50a, 50b, and 50c are connected to the IC. Thus, the currents of the motor windings of all three phases can be detected regardless of the direction of the current. By inserting a current detection resistor in each phase in this way, restrictions on current detection are reduced, so a relatively advanced control method such as vector control of an induction motor or a brushless motor is used. Widely used in equipment. Other operations are the same as those of the control circuit of FIG.

  As described above, a small and inexpensive motor control device can be realized by configuring the motor control device using the current detection circuit including the motor current detection IC of the present invention.

(Embodiment 11)
The current detection IC shown in the first to eighth embodiments, and a low resistance for current detection that is connected to one of input terminals via a protective element and directly connected to the other. Current detector.

  12 and 13 are block diagrams of the motor control device.

  In the motor control device of FIG. 12, the six IGBTs 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 constitute an inverter circuit. The lower three IGBTs 31a2, 31b2, and 31c2 are connected at their emitter terminals, which are power supply side terminals, connected to the current detection low resistance 50d, and connected at the other end to the negative side of the capacitor 108. Has been. In general, a rectifier circuit of a commercial AC power supply (not shown) is connected to both ends of the capacitor 108 and to the left side in FIG. 1, for example, a double voltage rectifier circuit of a single-phase AC 100V or a single-phase or three-phase AC 200V all. When a wave rectifier circuit is connected, a DC voltage of about 280 V is applied to the voltage across the capacitor 108. The current detector 106 includes the above-described low resistance 50d for current detection, the current detection IC 101, and the protection element 161d. The terminal of the low resistance 50d for current detection is connected to the emitter terminal side which is the minus power source side terminal of the lower three IGBTs 31a2, 31b2, and 31c2 via the protective element 161d, and the other end is directly It is connected to terminals T1 and T2 in the block diagram of the current detection IC shown in FIG. Terminals T <b> 1 and T <b> 2 are inputs of the differential amplifier circuit 105 inside the current detection IC 101. Since the detailed description of the IC has already been described above, it will be omitted.

  Next, the configuration of the motor control device in FIG. 13 will be described. The six IGBTs 31a1, 31a2, 31b1, 31b2, 31c1, and 31c2 constitute an inverter circuit. The current detection low resistances 50a, 50b, and 50c are separately connected to the emitter terminals that are the negative power supply side terminals of the three lower IGBTs 31a2, 31b2, and 31c2. That is, one end of the low resistance 50a is connected to the emitter side of the IGBT 31a2, one end of the low resistance 50b is connected to the emitter side of the IGBT 31b2, and one end of the low resistance 50c is connected to the emitter side of the IGBT 31c2. , 50b, 50c are connected to the negative side of the capacitor 108. In general, a rectifier circuit of a commercial AC power source (not shown) is connected to both ends of the capacitor 108 and to the left side in FIG. 2, for example, a double voltage rectifier circuit of a single-phase AC 100V or a single-phase or three-phase AC 200V all. When a wave rectifier circuit is connected, a DC voltage of about 280 V is applied across the capacitor 108. The current detector 107 includes the above-described low resistances 50a, 50b, and 50c for current detection, the current detection IC 103, and the protection elements 161a, 161b, and 161c. Both ends of the low resistance for current detection are terminals T1 and T2 in the block diagram of the current detection IC 103 shown in FIG. 4, with the other end connected directly to the IGBT 31a2 of the low resistance 50a via the protection element 161a. Connected to. The side connected to the IGBT 31b2 of the low resistance 50b is connected directly to the terminals T3 and T4 of the current detection IC 103 shown in FIG. 4 via the protective element 161b. The side connected to the IGBT 31c2 of the low resistance 50c is connected directly to the terminals T5 and T6 of the current detection IC 103 shown in FIG. 4 through the protective element 161c. Each terminal is an input of the differential amplifier circuit 105 inside the current detection IC 103. Since the detailed description of the IC has already been described above, it will be omitted.

  When the low resistance 50d for current detection shown in the motor control device of FIG. 12 and the low resistance 50a, 50b, 50c for current detection shown in the motor control device of FIG. There is a possibility that a high voltage of the inverter circuit is applied to the IGBT side. At this time, an excessive voltage may be applied to the input terminal T1 in the block diagrams of the ICs in FIGS. As a path through which current flows at this time, the surge protection element 161d in FIG. 12 and the protection element 161a, 161b, and 161c in FIG. Current flows through A device that suppresses current is used as the protective element. The impedances of the protection elements 161a, 161b, 161c, and 161d need to be sufficiently small with respect to the resistors R1 and R2 inside the current detection IC.

  Thereby, for example, when the low resistance for current detection connected to the outside of the IC becomes open, the IC bursts by preventing a large current from flowing from the terminal connected to the low resistance switching element side, Unsafeness such as ignition can be prevented.

(Embodiment 12)
As the protective elements 161a, 161b, 161c, and 161d shown in the eleventh embodiment, fuses that cut off current are used.

  The low resistance 50d for current detection shown in the motor control device of FIG. 12 and the low resistances 50a, 50b, 50c for current detection shown in the motor control device of FIG. 13 are normal, that is, the resistance value of the low resistance is the correct value. In the state where there is no burnout or solder removal, the current flowing through the protection elements 161a, 161b, 161c, 161d is very small. The fuse to be used may be one that can be cut off with a small current. For example, a current fuse of about 0.1 A is sufficient.

  The other detailed description is the same as that of the eleventh embodiment, and will be omitted.

(Embodiment 13)
Resistors are used as the protection elements 161a, 161b, 161c, and 161d shown in the eleventh embodiment.

  The low resistance 50d for current detection shown in the motor control device of FIG. 12 and the low resistances 50a, 50b, 50c for current detection shown in the motor control device of FIG. 13 are normal, that is, the resistance value of the low resistance is the correct value. In the state where there is no burnout or solder removal, the current flowing through the protection elements 161a, 161b, 161c, 161d is very small. As the resistors used, the resistance value is sufficiently smaller than the resistances R1 and R2 inside the current detection IC, and the low resistances 50a, 50b, and 50c for current detection are burned out or detached from the solder. When open, the high voltage of the inverter circuit is applied to the low resistance IGBT side, and the current flowing through the protection elements 161a, 161b, 161c, 161d when the current path is created due to dielectric breakdown etc. Select a resistance that can be sufficiently melted, or select a resistance value and capacity that can sufficiently suppress the current so as to prevent unsafe operations such as rupture and ignition of the current detection IC.

  The other detailed description is the same as that of the eleventh embodiment, and will be omitted.

(Embodiment 14)
This is a motor control device using the current detector shown in the eleventh to thirteenth embodiments. The detailed description is the same as in the tenth to thirteenth embodiments and will not be repeated.

  As described above, the motor current detection IC according to the present invention can be reduced in size, have a small number of components, have a small mounting area, and can achieve a reduction in cost as a current detection circuit. In addition, since the motor control device equipped with the motor current detection IC of the present invention can be reduced in size and cost, it can be used as a control device for a wide range of general motor-using devices such as washing machines, air conditioners and refrigerators. Useful.

31a1, 31a2, 31b1, 31b2, 31c1, 31c2 Switching elements 50a, 50b, 50c, 50d Current detection low resistance 101 Current detection IC
102 Control circuit 103 Current detection IC
104 control circuit 105 differential amplifier circuit 106 current detector 107 current detector 108 capacitor 110, 112 amplifier 111 comparator (comparison circuit)
113 amplification factor setting device 120, 121, 122 surge protection element 151 resin mold 152 lead frame 153 base substrate 154 chip 155 wire bonding 161a, 161b, 161c, 161d protection element 201 IC chip 202 aluminum wiring 203 bonding pad 204 surge protection element 205 contact hole T1, T2, T3, T4, T5, T6, T input terminal T7, T8, T9, T11, T12 output terminal T13, T14 gain setting terminal T15 power supply terminal T16 ground terminal

Claims (14)

A differential amplifier circuit; a comparison circuit; a pair of + and − input terminals of the differential amplifier circuit; and an output terminal of the differential amplifier circuit. The input terminal of the differential amplifier circuit receives a negative voltage input. The input terminal of the differential amplifier circuit has a function of cutting off a circuit of a terminal to which an excessive voltage is input when an excessive voltage is input, and the comparison circuit is one of the positive side and the negative side of the differential amplifier circuit. A motor current detection IC that compares a voltage input to the input terminal of the input terminal and a voltage determined by a detection value setting resistor connected to the outside and outputs the result. A differential amplifier circuit, a comparison circuit, a plurality of sets of + and − pairs of input terminals of the differential amplifier circuit, and an output terminal of the differential amplifier circuit, and the input terminal of the differential amplifier circuit has a negative voltage The input terminal of the differential amplifier circuit has a function of cutting off the circuit of the terminal to which the excessive voltage is input when the excessive voltage is input, and one end of the input of the plurality of comparison circuits is the difference between the input terminals. A voltage determined by a detection value setting resistor connected to the outside is connected to one of the input terminals of the positive side and the negative side of the dynamic amplifier circuit, and the other ends of the inputs of the plurality of comparison circuits are connected together. A motor current detection IC which is inputted and outputs the result of the plurality of outputs of the comparison circuit as one output. The motor current detection IC according to claim 1, wherein the amplification factor of the differential amplifier circuit is adjustable from the outside. The motor current detection IC according to any one of claims 1 to 3, wherein the power supply voltage is a single voltage. 5. The motor current detection device according to claim 1, wherein the surge protection element disposed at the + and − input terminals of the differential amplifier circuit is disposed between the positive side of the power supply voltage. 6. IC. The surge protection elements arranged at the + and-input terminals of the differential amplifier circuit are arranged in series with two surge protection elements having opposite polarities between the negative side of the power supply voltage. 5. The motor current detection IC according to any one of 4 above. The input terminal of + and-of a differential amplifier circuit melts | disconnects the wire bonding between the lead frame of an input terminal, and a silicon chip at the time of an excessive voltage input, The any one of Claim 1 to 4 characterized by the above-mentioned. Motor current detection IC. 5. The motor current according to claim 1, wherein the + and − input terminals of the differential amplifier circuit melt the vicinity of the bonding pad of the aluminum wiring on the silicon chip when an excessive voltage is input. IC for detection. 9. A motor current detector comprising the motor current detection IC according to claim 1 and a resistor connected between + and − input terminals of a differential amplifier circuit. A motor control device using the motor current detection IC according to claim 1. A motor comprising the motor current detection IC according to any one of claims 1 to 8, and a resistor connected to one of the + and-input terminals of the differential amplifier circuit via a protective element. Current detector. The motor current detector according to claim 11, wherein the protection element is a fuse for interrupting current. The motor current detector according to claim 11, wherein the protection element is a resistor. A motor control device using the motor current detector according to claim 11.

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