JP5319982B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device in which an overcurrent protection circuit is integrated.

  FIG. 6 is a circuit diagram showing a conventional example of an overcurrent protection circuit. As shown in FIG. 6, the conventional overcurrent protection circuit is inserted into the supply line of the voltage signal VX (= Vin−Vth) obtained by lowering the input voltage Vin by a predetermined threshold voltage Vth and the output current Iout. The voltage signal VY (= Vin−Iout × Rs) drawn from the low potential end of the sense resistor Rs is compared to generate the overcurrent protection signal Socp.

  In the semiconductor device formed by integrating the conventional overcurrent protection circuit, a wiring resistance component of a current line connecting the application terminal of the input voltage Vin and the load is used as the sense resistor Rs. There was also a thing.

Patent document 1 can be mentioned as an example of the prior art relevant to the above.
JP-A-7-287035

  Certainly, in the above-described conventional overcurrent protection circuit, the output current Iout is in the overcurrent state when the voltage drop (= Iout × Rs) at the sense resistor Rs becomes larger than the predetermined threshold voltage Vth. It is possible to generate the overcurrent protection signal Socp.

  However, when the wiring resistance component inside the semiconductor device is used as the sense resistor Rs, the resistance value varies greatly due to the thickness of the wiring (cross-sectional area of the wiring), so that the detection accuracy of the overcurrent protection circuit deteriorates. There was a problem of end. For example, when the resistance value of the sense resistor Rs is larger than the intended value, the voltage drop at the sense resistor Rs becomes large. Therefore, although the output current Iout is smaller than the intended threshold value, excessive current flows. A current state is erroneously detected, and the operation of the semiconductor device becomes unstable. On the contrary, when the resistance value of the sense resistor Rs is smaller than the intended value, the voltage drop at the sense resistor Rs becomes small, so that an overcurrent state is detected until an output current Iout larger than the intended threshold value flows. The safety of the semiconductor device is reduced.

  In view of the above problems, an object of the present invention is to provide a semiconductor device capable of improving the detection accuracy of an overcurrent protection circuit while using a wiring resistance component as a sense resistor.

  In order to achieve the above object, a semiconductor device according to the present invention compares a sense resistor, which is a wiring resistance component of a current line to be monitored, with a voltage drop across the sense resistor and a predetermined threshold voltage. An overcurrent protection circuit for generating a current protection signal, wherein the semiconductor device is further electrically connected to other circuit elements by the same process as the current line formation process. A dummy resistance which is a wiring resistance component of the dummy line formed separately and has a resistance value larger than the sense resistance; and first and second dummy pads respectively connected to both ends of the dummy resistance; The overcurrent protection circuit is configured to have a configuration (first configuration) including a threshold voltage adjustment unit for adjusting the threshold voltage.

  In the semiconductor device having the first configuration, the dummy resistor may be configured to be formed adjacent to the sense resistor (second configuration).

  The semiconductor device having the first or second configuration is electrically isolated from other circuit elements by filling the marginal margin of the dummy resistor in the same process as the current line forming process. A configuration (third configuration) may be formed by integrating the formed dummy layers.

  In the semiconductor device having any one of the first to third configurations, each of the first and second dummy pads may have a configuration in which a plurality of pads are formed as a set (fourth configuration). .

  In the semiconductor device having any one of the first to fourth configurations, the overcurrent protection circuit includes a first resistor having one end connected to one end of the sense resistor; and generates a reference current according to a reference voltage. And a constant current circuit that draws the reference current through a first resistor; and a comparator that compares the other end voltage of the first resistor with the other end voltage of the sense resistor to generate the overcurrent protection signal. (5th configuration).

  In the semiconductor device having the fifth configuration, the constant current circuit includes a second resistor connected between the other end of the first resistor and the ground end, and the reference voltage applied to one end of the second resistor. And a bias circuit to be applied (sixth configuration).

  In the semiconductor device having the sixth configuration, the bias circuit includes a first transistor connected between the first resistor and the second resistor, and a control terminal and a ground terminal of the first transistor. It is preferable to have a configuration (seventh configuration) including a second transistor that is connected and has the control voltage applied to the reference transistor.

  In the semiconductor device having the sixth configuration, the bias circuit includes a transistor connected between the first resistor and the second resistor, and the reference voltage and one end voltage of the second resistor coincide with each other. A configuration (eighth configuration) including an operational amplifier for controlling the conductivity of the transistor is preferable.

  In the semiconductor device having any one of the fifth to eighth configurations, the overcurrent protection circuit includes a resistance divider circuit that divides a predetermined internal voltage to generate the reference voltage, and the threshold value The voltage adjusting unit may be configured to include a trimming fuse connected in parallel to at least one of the resistance elements forming the resistance dividing circuit (ninth configuration).

  A semiconductor device adjustment method according to the present invention is a semiconductor device adjustment method having any one of the first to ninth configurations, and a constant current is passed between the first and second dummy pads. Measuring a voltage between the first and second dummy pads and calculating an actual resistance value of the dummy resistor from the measurement result; calculating a relative error of the actual resistance value with respect to an ideal resistance value of the dummy resistor; Calculating an estimated actual resistance value of the sense resistor based on the relative error and an ideal resistance value of the sense resistor; and using the threshold voltage adjusting unit based on the estimated actual resistance value of the sense resistor; And a step of adjusting the threshold voltage (a tenth configuration).

  The semiconductor device according to the present invention can improve the detection accuracy of the overcurrent protection circuit while using the wiring resistance component as the sense resistor.

  FIG. 1 is a circuit diagram showing an embodiment of a power supply IC according to the present invention. As shown in FIG. 1, the power supply IC according to the present embodiment includes an LDO [Low Drop-Out] regulator that generates a desired output voltage Vout from an input voltage Vin. A MOS [Metal Oxide Semiconductor] field effect transistor P1, a resistor R1 and a resistor R2, a capacitor C1, an error amplifier ERR, and a DC voltage source E1 are included.

  The source of the transistor P1 is connected to the application terminal of the input voltage Vin via the input pad T0. The drain of the transistor P1 is connected to the output terminal of the output voltage Vout, and is also connected to the ground terminal via the resistors R1 and R2. A capacitor C1 is connected between the lead-out terminal of the output voltage Vout and the ground terminal as smoothing means for the output voltage Vout. The non-inverting input terminal (+) of the error amplifier ERR is connected to the application terminal of the feedback voltage Vfb (the connection node of the resistors R1 and R2). The inverting input terminal (−) of the error amplifier ERR is connected to the application terminal of the reference voltage Vref (the positive terminal of the DC voltage source E1). The output terminal of the error amplifier ERR is connected to the gate of the transistor P1.

  The LDO regulator configured as described above generates a desired output voltage Vout from the input voltage Vin by controlling the conductivity of the transistor A1 so that the feedback voltage Vfb corresponding to the output voltage Vout matches the reference voltage Vref. To do.

  Further, the power supply IC of the present embodiment is formed by integrating a sense resistor Rs and an overcurrent protection circuit OCP in addition to the circuit elements forming the LDO regulator.

  The sense resistor Rs is current / voltage conversion means for detecting, as a voltage signal, the magnitude of the output current Iout that flows from the application terminal of the input voltage Vin toward the extraction terminal of the output voltage Vout. In the power supply IC of this embodiment, the sense resistor Rs uses a wiring resistance component of a current line (that is, a current line to be monitored by the overcurrent protection circuit OCP) in which the output current Iout flows inside the power supply IC. Is formed.

  The overcurrent protection circuit OCP is a means for generating an overcurrent protection signal Socp by comparing a voltage drop (= Iout × Rs) at the sense resistor Rs with a predetermined threshold voltage Vth, and the overcurrent protection signal Socp is , Output to the enable terminal of the error amplifier ERR forming the LDO regulator. With this configuration, when the voltage drop across the sense resistor Rs becomes larger than the predetermined threshold voltage Vth, it is detected that the output current Iout is in an overcurrent state, and the output operation of the LDO regulator is performed. Since the emergency stop can be performed, the safety of the power supply IC can be improved.

  However, as described in the background section, when the wiring resistance component inside the power supply IC is used as the sense resistance Rs, the resistance value greatly varies due to the thickness of the wiring (cross-sectional area of the wiring). If the threshold voltage Vth of the current protection circuit OCP is fixedly set, the detection accuracy of the overcurrent protection circuit OCP deteriorates.

  In order to solve this problem, it is desirable to measure the resistance value of the sense resistor Rs and adjust the threshold voltage Vth of the overcurrent protection circuit OCP based on the actually measured value, but the current line used as the sense resistor Rs Since the wiring resistance component is extremely small, it is extremely difficult to accurately measure the resistance value.

  Therefore, the power supply IC according to the present embodiment uses the dummy resistor Rd, the first dummy pad T1, and the second dummy pad T2 as means for estimating the value of the sense resistor Rs without actually measuring the resistance value. , And the overcurrent protection circuit OCP has a threshold voltage adjustment unit for adjusting the threshold voltage Vth based on the estimated actual resistance value of the sense resistor Rs. Yes.

  The dummy resistor Rd is a wiring resistance component of a dummy line formed electrically isolated from other circuit elements by the same process as the process of forming the current line (that is, the sense resistor Rs) through which the output current Iout flows. The resistance value is larger than that of the sense resistor Rs (the resistance value is large enough to be measured).

  The first dummy pad T1 and the second dummy pad T2 are respectively connected to both ends of the dummy resistor Rd, and serve as a contact point of the probe (test needle) when measuring the actual resistance value of the dummy resistor Rd. It is a pad (so-called EDS [Electrical Die Sorting] pad) and is not wire-bonded to the lead frame when packaging the power supply IC.

  FIG. 2 is a schematic diagram illustrating a layout example of the sense resistor Rs and the dummy resistor Rd. As shown in FIG. 2, the dummy resistor Rd is desirably formed adjacent to the sense resistor Rs. The dummy line used as the dummy resistor Rd is designed to have a narrower line width (about 1/10 in the example of FIG. 2) than the current line used as the sense resistor Rs. Further, the dummy line used as the dummy resistor Rd is routed so as to be folded back and forth between the first dummy pad T1 and the second dummy pad T2, and is used as a current line used as the sense resistor Rs. It is designed to have a longer line length (4-5 times in the example of FIG. 2).

  On the other hand, since the current line used as the sense resistor Rs and the dummy line used as the dummy resistor Rd are both formed in the same process, the thickness of each of them includes the manufacturing variation. Are identical.

  Therefore, when it is assumed that the line width and the line length of the sense resistor Rs and the line width and the line length of the dummy resistor Rd are formed without variation as designed values, each of the sense resistor Rs and the dummy resistor Rd The resistance values are varied while showing the same tendency due to only the thickness variation.

  For example, when the thickness of the dummy resistor Rd is smaller than the design value, the thickness of the sense resistor Rs is similarly smaller than the design value. Therefore, if the actual resistance value of the dummy resistor Rd is larger than the design value, the sense resistor Rs. Similarly, the actual resistance value should be larger than the design value. On the contrary, when the thickness of the dummy resistor Rd is larger than the design value, the thickness of the sense resistor Rs is also larger than the design value. Therefore, if the actual resistance value of the dummy resistor Rd is smaller than the design value, the sense resistor The actual resistance value of Rs should be smaller than the design value as well.

  Therefore, in the power supply IC of the present embodiment, instead of actually measuring the resistance value of the sense resistor Rs, the actual resistance value of the dummy resistor Rd is measured, and the actual resistance value of the sense resistor Rs is based on the actually measured value. Can be accurately estimated, and by adjusting the threshold voltage Vth of the overcurrent protection circuit OCP based on the estimated actual resistance value of the sense resistor Rs, the detection accuracy of the overcurrent protection circuit OCP is improved. It becomes possible to do.

  Further, the power supply IC of the present embodiment fills the marginal margin of the dummy resistor Rd in the same process as the formation process of the current line used as the sense resistor Rs and the dummy line used as the dummy resistor Rd. A dummy layer DL (see the hatched portion in FIG. 2) formed by being electrically separated from the circuit elements is integrated.

  By adopting such a configuration, the etching degree of the entire dummy line used as the dummy resistor Rd can be made uniform, and the thickness of the entire dummy line can be made uniform, so that the actual resistance value of the dummy resistor Rd is It is possible to maintain the good pairing between the sense resistor Rs and the dummy resistor Rd by avoiding variation for each part, and further, from the actual resistance value of the dummy resistor Rd to the actual resistance value of the sense resistor Rs. Can be accurately estimated.

  In the power supply IC of this embodiment, the first dummy pad T1 and the second dummy pad T2 are each formed as a set of a plurality of pads (two in the example of FIG. 2). With such a configuration, the contact resistance of the probe can be reduced, so that the actual resistance value of the dummy resistor Rd can be measured with high accuracy.

  Further, as shown in FIG. 2, the power supply IC according to the present embodiment actively uses a small margin portion existing between the dummy resistor Rd and the first and second dummy pads T1 and T2, thereby providing a spare. The dummy resistor Rd ′ and the first and second dummy pads T1 ′ and T2 ′ are integrated. With this configuration, even if the actual resistance value of the dummy resistor Rd cannot be measured for some reason, the actual resistance value of the spare dummy resistor Rd is measured, and based on this, the actual resistance value of the sense resistor Rs is measured. The resistance value can be estimated.

  Next, a procedure for adjusting the threshold voltage Vth of the overcurrent protection circuit OCP will be specifically described. First, the voltage Vm between the first and second dummy pads T1 and T2 is measured while flowing a constant current Im between the first and second dummy pads T1 and T2, and the actual resistance of the dummy resistor Rd is determined from the measurement result. The value RB (= Vm / Im) is calculated.

  Next, a relative error X (= (RB−RA) / RA) of the actual resistance value RB with respect to the ideal resistance value RA (design value) of the dummy resistor Rd is calculated. For example, when the ideal resistance value RA of the dummy resistor Rd is 100 [Ω] and the actual resistance value RB is 95 [Ω], the relative error X is −0.05.

  Next, the estimated actual resistance value RD (= (1 + X) × RC) of the sense resistor Rs is calculated based on the relative error X obtained earlier and the ideal resistance value RC (design value) of the sense resistor Rs. For example, when the ideal resistance value RC of the sense resistor Rs is 1 [Ω] and the previously obtained relative error X is −0.05, the estimated actual resistance value is 0.95 [Ω].

  Then, based on the estimated actual resistance value RD of the sense resistor Rs, the threshold voltage Vth is adjusted using the threshold voltage adjusting unit of the overcurrent protection circuit OCP. For example, when the estimated actual resistance value RD of the sense resistor Rs is larger than the ideal resistance value RC, the voltage drop at the sense resistor Rs increases, so the threshold voltage Vth of the overcurrent protection circuit OCP is increased accordingly. You may adjust to. On the contrary, when the estimated actual resistance value RD of the sense resistor Rs is smaller than the ideal resistance value RC, the voltage drop at the sense resistor Rs becomes small, so that the threshold voltage Vth of the overcurrent protection circuit OCP is adjusted accordingly. Adjust to a smaller value. By performing such adjustment, the power supply IC according to the present embodiment can improve the detection accuracy of the overcurrent protection circuit OCP while using the wiring resistance component as the sense resistor Rs.

  FIG. 3 is a circuit diagram showing a configuration example of the overcurrent protection circuit OCP. The overcurrent protection circuit OCP of this configuration example includes a resistor Ra, a constant current circuit CS, and a comparator CMP.

  The resistor Ra is a resistance element having one end connected to one end (high potential end) of the sense resistor Rs.

  The constant current circuit CS is a means for generating a reference current I according to the reference voltage Va and drawing the reference current I through the resistor Ra. The constant current circuit CS includes an npn bipolar transistor Qa, a pnp bipolar transistor Qb, and a resistor Rb. And Rc, variable resistors Rd and Re, and a capacitor Ca.

  The collector of the transistor Qa is connected to the other end of the resistor Ra. The emitter of the transistor Qa is connected to the ground terminal via the resistor Rb. The capacitor Ca is connected between the emitter of the transistor Qa and the ground terminal. The emitter of the transistor Qb is connected to the power supply terminal via the resistor Rc, and is also connected to the base of the transistor Qa. The collector of the transistor Qb is connected to the ground terminal. The base of the transistor Qb is connected to a reference voltage Va application terminal (a connection node between the variable resistor Rd and the variable resistor Re). The variable resistors Rd and Re are connected in series between the power supply terminal and the ground terminal, and form a resistance divider circuit that generates a reference voltage Va by dividing a predetermined internal voltage. This resistance divider circuit adjusts the reference voltage Va (and thus the threshold voltage Vth of the overcurrent protection circuit OCP) from when the overcurrent protection circuit OCP is integrated into the power supply IC until it is sealed with resin. Functions as a threshold voltage adjustment unit.

  In the constant current circuit CS configured as described above, the base voltage of the transistor Qa is a voltage level raised from the reference voltage Va by the drop voltage Vfb between the base and emitter of the transistor Qb, and the emitter voltage of the transistor Qa is The voltage level is reduced by the drop voltage Vfa between the base and emitter of the transistor Qa from the base voltage of the transistor Qa. Therefore, if the drop voltages Vfa and Vfb are equal to each other, the reference voltage Va is applied to one end of the resistor Rb. Therefore, the current value of the reference current I is equal to the voltage value of the reference voltage Va. The value divided by the resistance value (= Va / Rb).

  That is, in the constant current circuit CS of this configuration example, the bias circuit that applies the reference voltage Va to one end of the resistor Rb includes the transistor Qa connected between the resistor Ra and the resistor Rb, the base of the transistor Qa, and the ground terminal And a transistor Qb to which a reference voltage Va is applied at its base. With such a configuration, the constant current circuit CS can be formed extremely easily.

  The comparator CMP includes a voltage signal Vx (= Vin−I × Ra = Vin− (Ra / Rb) × Va) applied to the non-inverting input terminal (+) from the other end of the resistor Ra and the other end of the sense resistor Rs. This is means for comparing the voltage signal Vy (= Vin−Iout × Rs) applied from the (low potential end) to the inverting input end (−) to generate the overcurrent protection signal Socp. From another viewpoint, the comparator CMP compares the voltage drop at the sense resistor Rs (= Iout × Rs) with a predetermined threshold voltage Vth (= (Ra / Rb) × Va) and outputs an overcurrent protection signal. It can be said that it is a means to generate. The overcurrent protection signal Socp is low level (normal state) when the voltage level of the voltage signal Vy is higher than the voltage level of the voltage signal Vx, and conversely, the voltage level of the voltage signal Vy is the voltage level of the voltage signal Vx. It becomes high level (abnormal state) when it is lower than the level.

  In the overcurrent protection circuit OCP configured as described above, the overcurrent protection value Iocp can be calculated by the following equation (1).

  In the above equation (1), the parameter Va, the parameter Rs, and the parameters Ra and Rb indicate the voltage value of the reference voltage Va, the resistance value of the sense resistor Rs, and the resistance values of the resistors Ra and Rb, respectively. ing.

  As described above, in the overcurrent protection circuit OCP of this configuration example, the overcurrent protection value Iocp is set by causing the reference current I to flow through the resistor Ra, and as shown in the above equation (1), The protection value Iocp is not dependent on the voltage value of the input voltage Vin.

  Further, in the overcurrent protection circuit OCP of this configuration example, the reference voltage Va can be arbitrarily variably controlled in accordance with the resistance ratio of the variable resistors Rd and Re, so that the current value of the reference current I, The overcurrent protection value Iocp can be adjusted flexibly.

  FIG. 4 is a circuit diagram showing a configuration example of the variable resistors Rd and Re. As shown in FIG. 4, the variable resistor Rd includes resistors Rd0 to Rdm connected in series between the lead-out end of the reference voltage Va and the power supply end, and trimming fuses Fd1 to Fdm connected in parallel to the resistors Rd1 to Rdm, respectively. And comprising. The variable resistor Re includes resistors Re0 to Ren connected in series between the lead-out end of the reference voltage Va and the ground end, and trimming fuses Fe1 to Fen connected in parallel to the resistors Re1 to Ren, respectively. It consists of

  By adopting such a configuration, the fuses Fd1 to Fdm and Fe1 to Fen can be appropriately fused by laser fusing between the time when the overcurrent protection circuit OCP is integrated in the power supply IC and the time when the resin is sealed. It becomes possible to adjust the resistance ratio of the resistors Rd and Re (and hence the voltage value of the reference voltage Va).

  For example, when the estimated actual resistance value of the sense resistor Rs is larger than the ideal resistance value (design value), the voltage drop at the sense resistor Rs increases, so that the threshold voltage Vth of the overcurrent protection circuit OCP is adjusted accordingly. What is necessary is just to raise the voltage value of the reference voltage Va by fuse | melting the fuses Fd1-Fdm suitably in order to adjust large. On the other hand, when the estimated actual resistance value of the sense resistor Rs is smaller than the ideal resistance value, the voltage drop at the sense resistor Rs becomes small. Therefore, the threshold voltage Vth of the overcurrent protection circuit OCP is adjusted to be smaller accordingly. Therefore, the voltage value of the reference voltage Va may be lowered by appropriately fusing the fuses Fe1 to Fen.

  FIG. 5 is a circuit diagram showing a modification of the constant current circuit CS. As shown in FIG. 5, the constant current circuit CS of the present modification includes an operational amplifier AMP instead of the transistor Qb and the resistor Rc shown in FIG.

  A non-inverting input terminal (+) of the operational amplifier AMP is connected to an application terminal (a connection node of the variable resistors Rd and Re) of the reference voltage Va. The inverting input terminal (−) of the operational amplifier AMP is connected to the emitter of the transistor Qa. The output terminal of the operational amplifier AMP is connected to the base of the transistor Qa.

  That is, in the constant current circuit CS of this configuration example, the bias circuit that applies the reference voltage Va to one end of the resistor Rb includes the transistor Qa connected between the resistor Ra and the resistor Rb, and the reference voltage Va and the resistor Rb. The operational amplifier AMP controls the conductivity of the transistor Qa so that the voltages at one end coincide with each other. With such a configuration, the reference voltage Va is reliably applied to one end of the resistor Rb, so that the current value of the reference current I can be set with high accuracy.

  In the above embodiment, the configuration in which the present invention is applied to the power supply IC incorporating the LDO regulator has been described as an example. However, the application target of the present invention is not limited to this, and other semiconductors are described. The present invention can be widely applied to apparatuses.

  The configuration of the present invention can be variously modified within the scope of the present invention in addition to the above embodiment.

  The present invention is a technique that can be used for all semiconductor devices including an overcurrent protection circuit. For example, the present invention is a technique suitable for improving the safety of a power supply IC that supplies a drive voltage to a load.

These are the circuit diagrams which show one Embodiment of the power supply IC which concerns on this invention. These are schematic diagrams showing a layout example of the sense resistor Rs and the dummy resistor Rd. These are the circuit diagrams which show the example of 1 structure of the overcurrent protection circuit OCP. These are circuit diagrams which show the example of 1 structure of variable resistance Rd and Re. These are circuit diagrams showing a modification of the constant current circuit CS. These are circuit diagrams which show a prior art example of an overcurrent protection circuit.

Explanation of symbols

P1 P-channel MOS field effect transistor R1, R2 Resistor C1 Capacitor ERR Error amplifier E1 DC voltage source Rs Sense resistor Rd, Rd 'Dummy resistor OCP Overcurrent protection circuit T0 Input pad T1, T2, T1', T2 'Dummy pad DL Dummy layer CS constant current circuit Qa npn type bipolar transistor Qb pnp type bipolar transistor Ca capacitor Ra, Rb, Rc resistor Rd, Re variable resistor Rd0 to Rdm, Re0 to Ren resistor Fd1 to Fdm, Fe1 to Fen trimming fuse AMP operational amplifier

Claims (10)

A sense resistor that is a wiring resistance component of the current line to be monitored;
An overcurrent protection circuit for generating an overcurrent protection signal by comparing a voltage drop at the sense resistor with a predetermined threshold voltage;
A semiconductor device formed by integrating
The semiconductor device further includes:
A dummy resistance which is a wiring resistance component of a dummy line formed electrically isolated from other circuit elements in the same process as the current line formation process and has a resistance value larger than the sense resistance;
First and second dummy pads respectively connected to both ends of the dummy resistor;
It is formed by integrating
The semiconductor device according to claim 1, wherein the overcurrent protection circuit includes a threshold voltage adjustment unit for adjusting the threshold voltage.   The semiconductor device according to claim 1, wherein the dummy resistor is formed adjacent to the sense resistor. The semiconductor device further includes:
A dummy layer formed by being electrically separated from other circuit elements by filling the marginal margin of the dummy resistor by the same process as the current line formation process;
The semiconductor device according to claim 1, wherein the semiconductor device is integrated.   4. The semiconductor device according to claim 1, wherein each of the first and second dummy pads is formed as a set of a plurality of pads. The overcurrent protection circuit is
A first resistor having one end connected to one end of the sense resistor;
A constant current circuit that generates a reference current according to a reference voltage and draws the reference current through a first resistor;
A comparator that compares the other end voltage of the first resistor with the other end voltage of the sense resistor to generate the overcurrent protection signal;
The semiconductor device according to claim 1, comprising: The constant current circuit is:
A second resistor connected between the other end of the first resistor and the ground end;
A bias circuit for applying the reference voltage to one end of the second resistor;
The semiconductor device according to claim 5, comprising: The bias circuit includes:
A first transistor connected between the first resistor and the second resistor;
A second transistor connected between a control terminal of the first transistor and a ground terminal and having the reference voltage applied to its control terminal;
The semiconductor device according to claim 6, comprising: The bias circuit includes:
A transistor connected between the first resistor and the second resistor;
An operational amplifier that controls the conductivity of the transistor so that the reference voltage and the one-end voltage of the second resistor match.
The semiconductor device according to claim 6, comprising: The overcurrent protection circuit includes a resistance dividing circuit that divides a predetermined internal voltage to generate the reference voltage,
9. The semiconductor according to claim 5, wherein the threshold voltage adjusting unit includes a trimming fuse connected in parallel to at least one of the resistance elements forming the resistance dividing circuit. apparatus. A method for adjusting a semiconductor device according to claim 1, comprising:
Measuring a voltage between the first and second dummy pads while passing a constant current between the first and second dummy pads, and calculating an actual resistance value of the dummy resistor from the measurement result;
Calculating a relative error of an actual resistance value with respect to an ideal resistance value of the dummy resistor;
Calculating an estimated actual resistance value of the sense resistor based on the relative error and an ideal resistance value of the sense resistor;
Adjusting the threshold voltage using the threshold voltage adjustment unit based on the estimated actual resistance value of the sense resistor;
A method for adjusting a semiconductor device, comprising:

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