Current source circuit

Abstract

This invention provides a current source circuit that can accurately monitor the output current. [Solution] The current source circuit 20 includes a constant current circuit 22 that generates a constant current, an adjustment circuit 26 that adjusts the magnitude of the constant current generated in the constant current circuit, a first transistor MP1, a plurality of identical second transistors MP2_1 to MP2_20 that form a current mirror with the first transistor, and a measurement circuit 24 that measures the current. The current mirror is configured to output a current that is a copy of the constant current from the second transistor. The current output from the second transistor can be supplied to the corresponding circuit block and the measurement circuit. The measurement circuit measures the total current supplied from the plurality of second transistors. Based on the result of the measurement circuit measuring the total current, the adjustment circuit adjusts the magnitude of the constant current so that the magnitude of the total current approaches a predetermined current value.

Description

[Technical Field]

[0001] This disclosure relates to a current source circuit. [Background technology]

[0002] Conventionally, current source circuits have been used to supply current to circuit blocks. For example, Patent Document 1 discloses a current source circuit comprising a constant current circuit that generates a constant current and an output current mirror. The output current mirror has a P-channel type MOS (Metal Oxide Semiconductor) transistor on the input side and a MOS transistor on the output side, and mirrors the constant current generated in the constant current circuit to output it. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-73952

[0004] [overview] However, the inventors have come to recognize the following problem. When there are multiple circuit blocks to which current should be supplied, it is conceivable to provide multiple MOS transistors on the output side to form multiple current mirrors and supply current to the multiple circuit blocks. In this case, in order to adjust the supplied current, it is conceivable to take one of the multiple current mirrors as a representative and adjust the constant current so that the current output from that current mirror becomes the desired current.

[0005] However, because MOS transistors have variations in their characteristics, even if a representative current mirror outputs the desired current, other current mirrors may output currents that deviate from the desired value. Therefore, it is desirable to improve the accuracy of monitoring the currents output from multiple current mirrors.

[0006] This disclosure is made in view of these circumstances, and one of its exemplary objectives is to provide a current source circuit that enables improved accuracy in monitoring the output current.

[0007] A current source circuit in one aspect of the present disclosure includes a constant current circuit that generates a constant current, a regulating circuit that adjusts the magnitude of the constant current generated in the constant current circuit, a first transistor, a plurality of identical second transistors that each form a current mirror with the first transistor, and a measuring circuit that measures the current. The current mirror is configured to output a current from the second transistor that is a copy of the constant current. The current output from the second transistor can be supplied to the corresponding circuit block and the measuring circuit. The measuring circuit measures the total current supplied from the plurality of second transistors. Based on the measurement of the total current by the measuring circuit, the regulating circuit adjusts the magnitude of the constant current so that the magnitude of the total current approaches a predetermined current value.

[0008] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, etc., are also valid as aspects of this disclosure. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic block diagram of a semiconductor device according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a diagram illustrating an example of the state of the first changeover switch when current is supplied to the circuit block according to the same embodiment. [Figure 3] Figure 3 is a diagram illustrating an example of the state of the first and second selector switches when the output from the second transistor according to the same embodiment is supplied to the measurement circuit. [Figure 4] Figure 4 is a flowchart showing an example of the parameter determination process according to the same embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the current adjustment process according to the same embodiment. [Figure 6] Figure 6 is a block diagram of the semiconductor device 9 related to the comparative technology.

[0010] [Detailed explanation] (overview) This section outlines some exemplary embodiments of the present disclosure. This outline is intended to provide a basic understanding of the embodiments and to simplify some concepts of one or more embodiments, serving as a prelude to the more detailed descriptions that follow. It is not intended to limit the scope of the invention or disclosure. This outline is not a comprehensive overview of all possible embodiments, nor is it intended to identify essential elements of all embodiments or to delineate the scope of some or all aspects. For convenience, “one embodiment” may be used to refer to one or more embodiments (examples or variations) disclosed herein.

[0011] A current source circuit according to one embodiment includes a constant current circuit that generates a constant current, an adjustment circuit that adjusts the magnitude of the constant current generated in the constant current circuit, a first transistor, a plurality of identical second transistors that each form a current mirror with the first transistor, and a measurement circuit that measures the current. The current mirror is configured to output a current that is a copy of the constant current from the second transistor. The current output from the second transistor can be supplied to the corresponding circuit block and the measurement circuit. The measurement circuit measures the total current supplied from the plurality of second transistors. Based on the result of the measurement circuit measuring the total current, the adjustment circuit adjusts the magnitude of the constant current so that the magnitude of the total current approaches a predetermined current value.

[0012] In this configuration, the measurement circuit measures the total current supplied by multiple second transistors. As a result, the accuracy of monitoring the output current can be improved compared to measuring the current output from a single current mirror.

[0013] In one embodiment, the current source circuit may further include the same number of selector switches as there are second transistors. The selector switches may be configured to switch the destination of the current output from the corresponding second transistor between the corresponding circuit block and the measurement circuit.

[0014] In one embodiment, the current source circuit may further include a second changeover switch, with the first changeover switch being a changeover switch. The second changeover switch may be configured to switch the destination of the measurement terminal connected to the measurement circuit between a common output node of the multiple first changeover switches and the circuit under measurement. The current output from the second transistor may be supplied to the measurement circuit via the common output node and measurement terminal.

[0015] In one embodiment, the first transistor and the second transistor may be identical transistors. The adjustment circuit sets the target value of the current output from the second transistor to I TA The measurement circuit measures the total current and obtains the current value I ME Let N be the number of second transistors that supply current to the measurement circuit, I ME =N×I TA The magnitude of the constant current may be adjusted to achieve this result.

[0016] In one embodiment, the current source circuit may further include a memory. The memory may store data indicating parameter values ​​for a constant current circuit for adjusting the magnitude of the constant current, based on the results of the measurement circuit measuring the total current. The adjustment circuit may adjust the magnitude of the constant current based on the data stored in the memory.

[0017] In one embodiment, the constant current circuit may include an operational amplifier, a MOS transistor whose gate receives the output voltage of the operational amplifier, a voltage divider circuit that divides a reference voltage, and a resistor provided between the MOS transistor and ground. The MOS transistor may be configured to allow a constant current to flow. The voltage generated by the voltage divider circuit dividing the reference voltage may be input to the non-inverting input terminal of the operational amplifier. One end of the resistor on the MOS transistor side may be connected to the inverting input terminal of the operational amplifier. The adjustment circuit may adjust the constant current by changing the voltage division ratio of the reference voltage in the voltage divider circuit.

[0018] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Furthermore, the embodiments are illustrative and not limiting to the disclosure and invention, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure and invention.

[0019] In this specification, "member A is connected to member B" includes not only cases where member A and member B are directly connected physically, but also cases where member A and member B are indirectly connected via other members that do not substantially affect their electrical connection or impair the functions or effects produced by their combination.

[0020] Similarly, "member C is connected (provided) between member A and member B" includes not only cases where member A and member C, or member B and member C, are directly connected, but also cases where they are indirectly connected via other members that do not substantially affect their electrical connection state or impair the function or effect produced by their combination.

[0021] In this specification, the symbols attached to electrical signals such as voltage signals and current signals, or circuit elements such as resistors, capacitors, and inductors, shall represent their respective voltage values, current values, or circuit constants (resistance values, capacitance values, inductance), as required.

[0022] In this specification, "integrated integration" includes cases where all components of a circuit are formed on a semiconductor substrate or where the main components of a circuit are integrally integrated, and some resistors, capacitors, etc. may be provided outside the semiconductor substrate for adjusting circuit constants.

[0023] FIG. 1 is a schematic block diagram of a semiconductor device 1 according to an embodiment of the present disclosure. As shown in FIG. BL 1, the semiconductor device 1 includes N BL circuit blocks 10_1 to 10_20, a current source circuit 20, and measurement terminals T. Here, N BL is an integer of 2 or more, and in this embodiment, N

[0024] = 20. The semiconductor device 1 may be integrally integrated on one semiconductor chip. [[ID= / / 19]]

[0025] The circuit blocks, 10_1 to 10_20 are circuits that operate according to the current supplied from the current source circuit 20. The circuit blocks 10_1 to 10_20 may each be, for example, a DC / DC converter or the like. TR The current source circuit 20 can supply current to each of the circuit blocks 10_1 to 10_20. The current source circuit 20 according to this embodiment includes a constant current circuit 22, a measurement circuit 24, an adjustment circuit 26, a switch control circuit 28, a memory 30, a first transistor MP1, N SW identical second transistors MP2_1 to MP2_20, N

[0026] Here, N TR is an integer of 2 or more, and in this embodiment, N TR = N BL is. Also, NSW is 2 or more and N TR The integers are as follows, and in this embodiment, N SW =N TR Therefore, in this embodiment, N SW =N TR = 20

[0027] The constant current circuit 22 provides a constant current I CON This generates a constant current circuit 22 according to this embodiment, which includes a reference voltage source 220, a voltage divider circuit 222, an operational amplifier 224, a transistor MN1, and a first resistor R1.

[0028] The reference voltage source 220 is a reference voltage V REF Generates.

[0029] The voltage divider circuit 222 uses a reference voltage V REF The voltage is divided, and the voltage V + The voltage divider circuit 222 generates a reference voltage V. The voltage divider circuit 222 includes a second resistor R2 and a third resistor R3 connected in series. In this embodiment, the second resistor R2 and the third resistor R3 are variable resistors, respectively. The voltage divider circuit 222 generates a reference voltage V. REF Voltage V is generated by dividing the voltage. + V + =V REF It is expressed as ×R3 / (R2+R3). Voltage V + This is input to the non-inverting input terminal of the operational amplifier 224.

[0030] In this embodiment, transistor MN1 is composed of an N-channel MOS transistor. Transistor MN1 has the output voltage V of operational amplifier 224 connected to its gate. AMP Receiving a constant current I CON It is designed to allow for flow.

[0031] The first resistor R1 is placed between transistor MN1 and ground. Specifically, one end of the first resistor R1 is connected to the source of transistor MN1, and the other end of the first resistor R1 is connected to ground. Also, the end of the first resistor R1 on the transistor MN1 side is connected to the inverting input terminal of op-amp 224. A constant current I is supplied to the first resistor R1. CON When current flows, a voltage V is present at one end of the first resistor R1. - This occurs. Voltage V - V - =R1×I CON It is represented by the voltage V. - This is input to the inverting input terminal of the operational amplifier 224.

[0032] The operational amplifier 224 receives the voltage V input to its non-inverting input terminal. + And the V input to the inverting input terminal - The output voltage V is set to be the same as AMP It outputs a constant current I. CON is, I CON =V REF It is expressed as ×R3 / {R1×(R2+R3)}. Therefore, by changing the resistance values ​​of the first resistor R1, the second resistor R2, or the third resistor R3, the constant current I CON The magnitude can be adjusted. In this embodiment, the reference voltage V in the voltage divider circuit 222 REF By changing the voltage division ratio, i.e., R3 / (R2+R3), a constant current I can be generated. CON The size is adjusted.

[0033] The first transistor MP1 in this embodiment is composed of a P-channel type MOS transistor. The source of the first transistor MP1 is the power supply voltage V DD A constant current I is supplied, and the gate of the first transistor MP1 is connected to the drain of the first transistor MP1. The first transistor MP1 is connected in series with transistor MN1. Specifically, the drain of the first transistor MP1 is connected to the drain of transistor MN1. This provides a constant current I CON This also flows to the first transistor MP1.

[0034] N TR The second transistors MP2_1 to MP2_20 each form a current mirror with the first transistor MP1. The current mirror is a constant current I CON The current I1~I copied 20 This is configured to output from the second transistors MP2_1 to MP2_20.

[0035] Current I1~I output from the second transistor MP2_1~MP2_20 20 Each of these can be supplied to the corresponding circuit blocks 10_1 to 10_20 and the measurement circuit 24. Here, the second transistor MP2_x (x is 1 or greater and N) TR The following integers apply. The same applies to the signs of the circuit block, the current output from the second transistor, and the first toggle switch. ) corresponds to circuit block 10_x.

[0036] In this embodiment, the second transistors MP2_1 to MP2_20 are each of the same type of P-channel MOS transistor. Also in this embodiment, the first transistor MP1 and the second transistors MP2_1 to MP2_20 are each of the same type of transistor. The power supply voltage V is connected to the source of each of the second transistors MP2_1 to MP2_20. DD The following is supplied. The gates of the second transistors MP2_1 to MP2_20 are connected to the gate of the first transistor MP1.

[0037] The second changeover switch SW21 is configured to allow switching the connection destination of the measurement terminal T connected to the measurement circuit 24 between the common output node N1 of the first changeover switches SW1 to SW20 and the circuit to be measured.

[0038] The first changeover switch SWx controls the current I output from the corresponding second transistor MP2_x. xThe destination of the power supply is configured to be switchable between the corresponding circuit block 10_x and the measurement circuit 24. In this embodiment, the first changeover switch SWx switches the destination of the drain of the second transistor MP2_x between the corresponding circuit block 10_x and a common output node N1.

[0039] When the drain of the second transistor MP2_x is connected to the corresponding circuit block 10_x, the current I output from the second transistor MP2_x x This is supplied to the corresponding circuit block 10_x. Also, when the measurement terminal T is connected to the common output node N1 via the second changeover switch SW21, and the drain of the second transistor MP2_x is connected to the common output node N1, the current I output from the second transistor MP2_x is supplied. x However, it is supplied to the measurement circuit 24 via a common output node N1 and measurement terminal T.

[0040] Figure 2 shows the currents I1 to I in circuit blocks 10_1 to 10_20 according to this embodiment. 20 This diagram illustrates an example of the state of the first changeover switches SW1 to SW20 when the supply is active.

[0041] In the example shown in Figure 2, the first selector switches SW1 to SW20 each connect the drain of the corresponding second transistor among the second transistors MP2_1 to MP20 to the corresponding circuit block among the circuit blocks 10_1 to 10_20. This allows the currents I1 to I2 output from the second transistors MP2_1 to MP2_20 to be connected. 20 These are supplied to the corresponding circuit block among circuit blocks 10_1 to 10_20, respectively.

[0042] Figure 2 shows an example where all of the first selector switches SW1 to SW20 connect the drains of the corresponding second transistors MP2_1 to MP2_20 to the corresponding circuit blocks 10_1 to 10_20. However, this is not limited to this example; some of the first selector switches SW1 to SW20 may connect the drains of the corresponding second transistors to the corresponding circuit blocks. This makes it possible to supply current to some of the circuit blocks 10_1 to 10_20.

[0043] Figure 3 shows the currents I1 to I20 output from the second transistors MP2_1 to MP2_20 according to this embodiment. 20 This diagram illustrates an example of the state of the first changeover switches SW1 to SW20 and the second changeover switch SW21 when the voltage is supplied to the measurement circuit 24.

[0044] As shown in Figure 3, the first selector switches SW1 to SW20 each connect the drain of the corresponding second transistor (MP2_1 to MP2_20) to the common output node N1. The second selector switch SW21 connects the measurement terminal T to the common output node N1. Therefore, the currents I1 to I output from the second transistors MP2_1 to MP2_20 are connected. 20 All of this is supplied to the measurement circuit 24. As a result, the measurement circuit 24 receives I SUM1 =I1+I2+···+I 20 The total current I is represented by SUM1 It will be supplied.

[0045] Figure 3 shows an example where all drains of the second transistors MP2_1 to MP2_20 are connected to a common output node N1. However, this is not limited to this example; the drains of some of the second transistors MP2_1 to MP2_20 may be connected to the common output node N1. In this case, the measurement circuit 24 is supplied with current output from some of the second transistors MP2_1 to MP2_20.

[0046] Returning to Figure 1, let's explain the measurement circuit 24. The measurement circuit 24 measures current. In this embodiment, the measurement circuit 24 measures the current I1 to I supplied from the second transistors MP2_1 to MP2_20. 20 And it can measure the current flowing through the circuit to be measured. The measurement circuit 24 according to this embodiment is N TR Current I1~I supplied from the second transistors MP2_1~MP2_20 20 Total current I SUM1 The measurement circuit 24 measures the total current I SUM1 The current value I obtained by measuring it ME1 Measurement signal S that indicates ME1 This can be transmitted to the adjustment circuit 26.

[0047] The measurement circuit 24 can measure the current flowing through a circuit to be measured when the measurement terminal T is connected to the circuit to be measured via the second changeover switch SW21. In this way, it is possible to switch the circuit to which the current is to be measured in accordance with the switching of the second changeover switch SW21.

[0048] Memory 30 stores various types of data. Memory 30 may be, for example, OTP (One Time Programmable) memory, MTP (Multiple Time Programmable) memory, or flash memory. Memory 30 is a constant current I CON The memory may store data for adjusting the constant current circuit 22, for example, data showing the parameter values ​​for the constant current circuit 22. Specifically, the memory 30 stores data for adjusting the total current I of the measurement circuit 24. SUM1 Based on the measurement results, constant current I CON Data indicating the parameter values ​​for the constant current circuit 22 used to adjust the magnitude may be stored.

[0049] The adjustment circuit 26 controls the constant current I generated in the constant current circuit 22. CON The magnitude is adjusted. For example, the adjustment circuit 26 adjusts the reference voltage V in the voltage divider circuit 222. REF By changing the voltage division ratio, a constant current I CONcan be adjusted. Specifically, the adjustment circuit 26 changes the resistance values of the second resistor R2 and the third resistor R3 included in the constant current circuit 22 using the adjustment signal S TRIM1 to adjust the constant current I CON . Note that the adjustment circuit 26 may be provided as a part of the constant current circuit 22

[0050] The adjustment circuit 26 adjusts the magnitude of the constant current I SUM1 based on the result of the measurement circuit 24 measuring the total current I SUM1 so that the magnitude of the total current I TA1 approaches a predetermined current value I CON . Thereby, each value of the currents I1 to I 20 output from the second transistors MP2_1 to MP2_20 can be made to approach a desired current value. The adjustment circuit 26 may adjust the constant current I ME1 based on the measurement signal S CON from the measurement circuit 24

[0051] Specifically, with the target value of each of the currents I1 to I 20 output from the second transistors MP2_1 to MP2_20 being I TA2 , the magnitude of the constant current I ME1 = I TA1 = N TR × I TA2 , the magnitude of the constant current I CON may be adjusted. At this time, it is assumed that all of the currents I1 to I 20 are supplied to the measurement circuit 24. For example, when the current value I ME1 indicated by the measurement signal S ME1 is smaller than N TR × I TA2 , the adjustment circuit 26 increases the constant current I CON . On the other hand, when the current value I ME1 indicated by the measurement signal S ME1 is larger than N TR × I TA2 , the adjustment circuit 26 decreases the constant current I CON

[0052] Here, the currents I1 to I 20 ​In some cases, a portion of this current may be supplied to the measurement circuit 24. In this case, the number of second transistors MP2_1 to MP2_20 that supply current to the measurement circuit 24 is N. TRME As such, the adjustment circuit 26 is I ME1 =N TRME ×I TA2 Therefore, a constant current I CON You may adjust the size.

[0053] The adjustment circuit 26 controls the total current I measured by the measurement circuit 24. SUM1 Based on the measurement results, constant current I CON Data D shows the parameter values ​​for adjusting the size. TRIM1 The values ​​may be stored in memory 30. The parameters are, for example, the reference voltage V in the voltage divider circuit 222. REF The voltage division ratio may be such as the voltage division ratio. The adjustment circuit 26, for example, receives the measurement signal S ME1 The current value I shown ME1 and the target current value I TA1 If the difference is less than or equal to a predetermined threshold, data D will show the value of the partial pressure ratio at that time. TRIM1 You may store this in memory 30.

[0054] The adjustment circuit 26 uses data D stored in memory 30, which indicates the parameter values ​​related to the constant current circuit 22. TRIM2 Based on constant current I CON This can be adjusted. This data D TRIM2 The measurement circuit 24 is the total current I SUM1 The data may be generated based on the results of the measurement. In this way, constant current I in memory 30 CON Data D shows the parameter values ​​for adjusting the settings. TRIM1 Once it is stored, the adjustment circuit 26 then adjusts the data D stored in memory 30. TRIM2 Using a constant current I CON It can be adjusted appropriately.

[0055] The switch control circuit 28 controls the control signal S SWThe switch control circuit 28 generates a status signal S that indicates the state of the first selector switches SW1 to SW20 and the second selector switch SW21. STATE This may be transmitted to the measurement circuit 24 and the adjustment circuit 26.

[0056] Status signal S STATE For example, this may indicate whether each of the first selector switches SW1 to SW20 connects the drain of the corresponding second transistor to the common output node N1 or the corresponding circuit block. Also, the status signal S STATE This may indicate whether the second changeover switch SW21 is connected to the common output node N1 or the circuit under measurement, or to the measurement terminal T.

[0057] Figure 4 is a flowchart showing an example of the parameter determination process according to this embodiment. The parameter determination process involves the total current I SUM1 Based on the measurement results, constant current I CON Data D shows the parameter values ​​for adjusting the size. TRIM1 This is the process for storing the data in memory 30. Below, an example of the operation flow of the current source circuit 20 in the parameter determination process will be explained according to the flowchart shown in Figure 4.

[0058] First, the switch control circuit 28 switches the second changeover switch SW21 so that the measurement terminal T is connected to the common output node N1 of the second transistors MP2_1 to MP2_20 (S101).

[0059] Next, the switch control circuit 28 controls the currents I1 to I output from the second transistors MP2_1 to MP2_20. 20The first selector switches SW1 to SW20 are switched so that the current is supplied to the measurement circuit 24 (S103). Specifically, the switch control circuit 28 switches each of the second selector switches SW1 to SW20 so that the drains of the second transistors MP2_1 to MP2_20 are connected to the common output node N1.

[0060] Next, the adjustment circuit 26 controls the constant current I generated in the constant current circuit 22. CON The size is initially set to I INIT Set to (S105). This sets the initial value INIT Constant current I set to CON The current I1~I copied 20 These currents I1~I are output from the second transistors 2_1~2_20. 20 All of these are supplied to the measurement circuit 24 via a common output node N1 and measurement terminal T. The adjustment circuit 26 controls the constant current I CON Initial value I INIT When setting it to, for example, constant current I CON The size is initially set to I INIT Data D for making TRIM2 You may reference it from memory 30.

[0061] Next, the measurement circuit 24 is N SW The total current I supplied from the second transistors MP2_1 to MP2_20 SUM1 The measurement is taken (S107). Next, the adjustment circuit 26 measures the total current I in S107 when the measurement circuit 24 is SUM1 Based on the measurement results, the total current I SUM1 The magnitude of the current value I is predetermined. TA1 To approach this, a constant current I CON Adjust the size (S109).

[0062] Next, the adjustment circuit 26 indicates the value of the parameter related to the constant current circuit 22, constant current I CON Data D for adjusting the size TRIM1 The constant current I is stored in memory 30 (S111). For example, in S109, the constant current I CONAs a result of adjusting the size, the measured current value I ME1 The target current value I TA1 If the error is below the threshold, then data D shows the voltage division ratio of the voltage divider circuit 222 at that time. TRIM1 This may be stored in memory 30. If the error is greater than the threshold, the processes in S107 and S109 may be repeated as needed.

[0063] Figure 5 is a flowchart showing an example of the current adjustment process according to this embodiment. The current adjustment process may be performed, for example, when the semiconductor device 1 is started up. When the current adjustment process is started, the memory 30 contains the constant current I generated in the parameter determination process. CON Data D for adjustment TRIM1 It is assumed that this is stored in memory. Below, an example of the operation flow of the current source circuit 20 in the current adjustment process will be explained according to the flowchart shown in Figure 5.

[0064] First, the adjustment circuit 26 indicates the value of the parameters related to the constant current circuit 22, constant current I CON To adjust data D TRIM2 Read this data from memory 30 (S201). TRIM2 This is the data D generated in the parameter determination process described above. TRIM1 This may be the case. Next, the adjustment circuit 26 reads the data D in S201. TRIM2 Based on this, constant current I CON Adjust (S203).

[0065] Next, the switch control circuit 28 controls the currents I1 to I output from the second transistors MP2_1 to MP2_20. 20 However, the first selector switches SW1 to SW20 are switched so that current is supplied to the corresponding circuit blocks 10_1 to 10_20 (S205). As a result, each of the circuit blocks 10_1 to 10_20 receives current I1 to I from the corresponding second transistors MP2_1 to MP2_20. 20 It will be supplied.

[0066] The semiconductor device 1 and its operation according to this embodiment have been described above. The current source circuit 20 provided in the semiconductor device 1 according to this embodiment provides a constant current I CON A constant current circuit 22 that generates current, a first transistor MP1, and multiple identical (N) transistors that form a current mirror with the first transistor MP1. TR It has two transistors MP2_1 to MP2_20 and a current measuring circuit 24. The current mirror has a constant current I CON The current I1~I copied 20 The currents I1 to I are output from the second transistors MP2_1 to MP2_20. 20 This can be supplied to the corresponding circuit blocks 10_1 to 10_20 and the measurement circuit 24. The measurement circuit 24 receives the total current I supplied from multiple second transistors MP2_1 to MP2_20. SUM1 Measure.

[0067] In this configuration, the measurement circuit 24 receives the total current I supplied from multiple second transistors MP2_1 to MP2_20. SUM1 This measures the current output. Therefore, it is possible to improve the accuracy of monitoring the output current compared to measuring the current output from a single current mirror. The improvements in current monitoring accuracy will be explained in detail with reference to the following comparative techniques.

[0068] Figure 6 is a block diagram of the semiconductor device 9 relating to the comparative technology. The semiconductor device 9 relating to the comparative technology differs from the semiconductor device 1 according to this embodiment in the configuration of the current source circuit 90. Specifically, in this embodiment, the current source circuit 20 outputs currents I1 to I from a plurality of second transistors MP2_1 to MP2_20. 20 Total current I SUM1 In contrast to the above, the current source circuit 90 related to the comparative technology differs in that it measures the current output from a single transistor.

[0069] The current source circuit 90 relating to the comparative technology includes a constant current circuit 22, a measurement circuit 94, an adjustment circuit 96, a first transistor MP1, third transistors MP3_1 to MP3_20, and a measurement transistor MPT.

[0070] The third transistors MP3_1 to MP3_20 are all identical P-channel MOS transistors and form a current mirror with the first transistor MP1. These current mirrors each have a constant current I CON Copy this and apply current I to the corresponding circuit blocks 10_1~10_20. 901 ~I 920 To supply.

[0071] The measuring transistor MPT is composed of P-channel type MOS transistors of the same type as the third transistors MP3_1 to MP3_20, and forms a current mirror with the first transistor MP1. This current mirror provides a constant current I CON Copy and paste the current I TEST This is supplied to the measurement circuit 94.

[0072] The measurement circuit 94 measures current I TEST The measurement signal S is used to measure the measurement result. ME9 The measurement signal S from the measurement circuit 94 is transmitted to the adjustment circuit 96. ME9 Based on this, adjustment signal S TRIM9 Using a constant current I CON Adjust.

[0073] Here, the current I flowing through the measuring transistor MPT is TEST The constant current I flowing through the first transistor MP1 in relation to this current I CON The variation (3σ) is 0.1 μA, and the current I flowing through the measuring transistor MPT is TEST The current I flowing through the third transistor MP3_1 is 901 Let's assume the variation (3σ) is 0.1 μA.

[0074] Like the comparison technique, current I TEST Measure the current I using the voltage divider circuit 222. TESTEven if it is precisely adjusted to 1 μA, the constant current I CON A variation of 0.1 μA occurs, and the constant current I CON This becomes 1μA ± 0.1μA. Furthermore, current I 901 is a constant current I CON Because there is a variation of 0.1 μA, the current I 901 is current I TEST In contrast, the total is {(0.1) 2 +(0.1) 2} 1 / 2 It has a variation of =0.141 (μA). That is, current I 901 This becomes 1μA ± 0.141μA. Similarly, current I 902 ~I 920 This also becomes 1 μA ± 0.141 μA.

[0075] Compared to the semiconductor device 9 of the comparative technology, the semiconductor device 1 according to this embodiment has currents I1 to I output from the second transistors MP2_1 to MP2_20. 20 Total current I SUM1 Measure the total current I SUM1 Adjust the current I1~I 20 This can improve the accuracy of each monitoring step.

[0076] The constant current I flowing through the first transistor MP1 is relative to the current I1 flowing through the second transistor MP2_1. CON The error (3σ) is set to 0.1μA, similar to the comparison technique. Similarly, the currents I2 to I2 flowing through the second transistors MP2_2 to MP2_20 are also set. 20 Constant current I for each of them CON Let the error be 0.1 μA. TR Using the second transistors MP2_1 to MP2_20, the total current I SUM1 to N TR When adjusted to ×1μA, constant current I CON The variation is 1 / (N TR ) 1 / 2 It doubles. That is, constant current I CON This is 1μA±0.1 / (N TR ) 1 / 2 This becomes μA.

[0077] As a result, the current I1 flowing through the second transistor MP2_1 is {(0.1)} relative to the target of 1μA. 2 +(0.1) 2 / N TR} 1 / 2 It has a variation of (μA) (3σ). TR If we set =20, the variation will be 0.102μA. That is, current I1 will be 1μA ± 0.102μA. Similarly, current I2 ~ I 20 This also results in 1 μA ± 0.102 μA.

[0078] Thus, compared to the comparative technology, in this embodiment, the output currents I1 to I 20 The variation in each of these can be reduced, and in one example, it can be reduced from 0.141 μA to 0.102 μA. As a result, in this embodiment, the output currents I1 to I 20 This makes it possible to improve the accuracy of monitoring the current I1~I 20 Because the variation in the output current I1~I becomes smaller, 20 The accuracy of the current value can also be improved.

[0079] Furthermore, in the semiconductor device 9 of the comparative technology, the measurement accuracy of the current decreases when measuring a low current of 1 μA. For example, suppose the measurement error of the measurement circuit 94 of the comparative technology is ±0.2 μA. In this case, when the measurement circuit 94 measures a current of 1 μA, the measurement error becomes 20%.

[0080] In contrast, in the semiconductor device 1 according to this embodiment, the measured current is N of the current measured in the comparative technique. TR Double the total current I SUM1 In this embodiment, the semiconductor device 1 has N TR If, for example, it is 20, then the current I1~I 20 When each of them is 1 μA, the total current measured is I SUM1 This becomes 20 μA. Therefore, even if the measurement error of the measurement circuit 24 is ±0.2 μA, similar to the measurement circuit 94 related to the comparative technology, the total current I SUM1The measurement error is 1%. Thus, according to the semiconductor device 1 of this embodiment, the currents I1 to I 20 The measurement accuracy can also be improved; in one example, it can be improved by 20 times.

[0081] (Variation 1) In the above embodiment, the adjustment circuit 26 controls the reference voltage V in the voltage divider circuit 222. REF By changing the voltage division ratio, a constant current I CON An example of adjusting the constant current I was explained. However, the adjustment circuit 26 can also change the resistance value of the first resistor R1 between transistor MN1 and ground to control the constant current I. CON You may adjust it.

[0082] (Modification 2) The parameter determination process described with reference to Figure 4 and the current adjustment process described with reference to Figure 5 do not necessarily have to be performed in the order shown. If necessary, multiple steps may be performed in a different order, or multiple steps may be performed in parallel.

[0083] (Variation 3) In the above embodiment, in the parameter determination process, constant current I CON An example was described in which, after the process of adjusting the magnitude (S109) is performed, data indicating the parameter value for adjusting the magnitude of the constant current is stored (S111). The process in S109 is not necessarily performed. In this case, the measurement circuit 24 or the adjustment circuit 26, for example, the measured total current I SUM1 The current value, the target current value for the total current, and the parameter values ​​may be referenced, and the parameter values ​​may be determined based on that table. This table may be stored, for example, in memory 30.

[0084] (Modification 4) In the above embodiment, an example was described in which the first transistor MP1 and the second transistors 2_1 to 2_20 are each composed of MOS transistors. However, the embodiment is not limited to this, and the first transistor MP1 and the second transistors 2_1 to 2_20 may be composed of, for example, bipolar transistors.

[0085] (Variation 5) In the above embodiment, an example was described in which a corresponding first changeover switch SW1 to SW20 is provided for each of the second transistors MP2_1 to MP2_20. However, the invention is not limited to this, and the first changeover switches may be provided for only some of the second transistors MP2_1 to MP2_20. For example, the first changeover switches SW1 to SW15 may be provided for the second transistors MP2_1 to MP2_15, and the current output from the second transistors MP2_16 to MP2_20 may be supplied to the corresponding circuit blocks 10_16 to 10_20 without going through the first changeover switches.

[0086] (Experimental variation 6) In the above embodiment, the number of circuit blocks 10_1 to 10_20 is N. BL and the number of second transistors MP2_1~M2_20 N TR An example where N is the same was explained. This is not limited to this example. BL is, N TR It may be less than that. In this case, for example, the current output from multiple second transistors may be supplied to a common circuit block.

[0087] (supplement) While the embodiments described herein have been explained using specific terminology, this explanation is merely illustrative to aid understanding and does not limit the scope of this disclosure or the claims. The scope of the present invention is defined by the claims. Furthermore, not only the embodiments described herein, but also embodiments, examples, and modifications not described herein are included in the scope of the present invention.

[0088] (Note) The technology disclosed herein can be understood in one respect as follows:

[0089] (Item 1) A constant current circuit that generates a constant current, An adjustment circuit for adjusting the magnitude of the constant current generated in the constant current circuit, The first transistor and Multiple identical second transistors, each forming a current mirror with the first transistor, It has a measuring circuit for measuring current, The current mirror is configured to output a current copied from the constant current from the second transistor. The current output from the second transistor can be supplied to the corresponding circuit block and the measurement circuit. The measurement circuit measures the total current supplied from the plurality of second transistors, The adjustment circuit adjusts the magnitude of the constant current based on the result of the measurement circuit measuring the total current, so that the magnitude of the total current approaches a predetermined current value. Current source circuit.

[0090] (Item 2) The system further comprises the same number of selector switches as the aforementioned plurality of second transistors, The aforementioned changeover switch is configured to allow the current output from the corresponding second transistor to be supplied to either the corresponding circuit block or the measurement circuit. The current source circuit described in item 1.

[0091] (Item 3) The aforementioned changeover switch is designated as the first changeover switch, and the system further includes a second changeover switch. The second changeover switch is configured to allow switching the connection destination of the measurement terminal connected to the measurement circuit between a common output node of multiple first changeover switches and the circuit to be measured. The current output from the second transistor is supplied to the measurement circuit via the common output node and the measurement terminal. The current source circuit described in item 2.

[0092] (Item 4) The first transistor and the second transistor are identical transistors, The adjustment circuit sets the target value of the current output from the second transistor to I TA The measurement circuit measures the total current and obtains a current value I ME Let N be the number of second transistors that supply current to the measurement circuit, I ME =N×I TA The magnitude of the constant current is adjusted so that this occurs. A current source circuit as described in any one of items 1 through 3.

[0093] (Item 5) It has even more memory, The memory stores data indicating the values ​​of parameters related to the constant current circuit for adjusting the magnitude of the constant current, based on the results of the measurement circuit measuring the total current. The adjustment circuit adjusts the magnitude of the constant current based on the data stored in the memory. A current source circuit as described in any one of items 1 through 4.

[0094] (Item 6) The constant current circuit includes an operational amplifier, a MOS transistor that receives the output voltage of the operational amplifier at its gate, a voltage divider circuit that divides the reference voltage, and a resistor provided between the MOS transistor and ground. The MOS transistor is provided so that the constant current flows through it. The voltage generated by the voltage divider circuit dividing the reference voltage is input to the non-inverting input terminal of the operational amplifier. One end of the resistor on the MOS transistor side is connected to the inverting input terminal of the operational amplifier. The adjustment circuit adjusts the constant current by changing the voltage division ratio of the reference voltage in the voltage divider circuit. A current source circuit as described in any one of items 1 through 5. [Explanation of Symbols]

[0095] 1 Semiconductor device, 10_1~10_20 Circuit block, 20 Current source circuit, 22 Constant current circuit, 24 Measurement circuit, 26 Adjustment circuit, 28 Switch control circuit, 30 Memory, 220 Reference voltage source, 222 Voltage divider circuit, 224 Operational amplifier, MN1 Transistor, MP1 First transistor, MP2_1~MP2_20 Second transistor, SW1~SW20 First selector switch, SW21 Second selector switch, T Measurement terminal, R1 First resistor, R2 Second resistor, R3 Third resistor.

Claims

1. A constant current circuit that generates a constant current, An adjustment circuit for adjusting the magnitude of the constant current generated in the constant current circuit, The first transistor and Multiple identical second transistors, each forming a current mirror with the first transistor, It has a measuring circuit for measuring current, The current mirror is configured to output a current copied from the constant current from the second transistor. The current output from the second transistor can be supplied to the corresponding circuit block and the measurement circuit. The measurement circuit measures the total current supplied from the plurality of second transistors, The adjustment circuit adjusts the magnitude of the constant current based on the result of the measurement circuit measuring the total current, so that the magnitude of the total current approaches a predetermined current value. Current source circuit.

2. The system further comprises the same number of selector switches as the aforementioned plurality of second transistors, The aforementioned changeover switch is configured to allow the current output from the corresponding second transistor to be supplied to either the corresponding circuit block or the measurement circuit. The current source circuit according to claim 1.

3. The aforementioned changeover switch is designated as the first changeover switch, and the system further includes a second changeover switch. The second changeover switch is configured to allow switching the connection destination of the measurement terminal connected to the measurement circuit between a common output node of multiple first changeover switches and the circuit to be measured. The current output from the second transistor is supplied to the measurement circuit via the common output node and the measurement terminal. The current source circuit according to claim 2.

4. The first transistor and the second transistor are each identical type of transistor. The adjustment circuit sets the target value of the current output from the second transistor to I ＴＡ The measurement circuit measures the total current and obtains a current value I ＭＥ Let N be the number of second transistors that supply current to the measurement circuit, I ＭＥ = N × I ＴＡ The magnitude of the constant current is adjusted so that this occurs. The current source circuit according to claim 1.

5. It has even more memory, The memory stores data indicating the determination of parameter values ​​for the constant current circuit for adjusting the magnitude of the constant current, which are determined based on the results of the measurement circuit measuring the total current. The adjustment circuit adjusts the magnitude of the constant current based on the data stored in the memory. The current source circuit according to claim 1.

6. The constant current circuit includes an operational amplifier, a MOS transistor that receives the output voltage of the operational amplifier at its gate, a voltage divider circuit that divides the reference voltage, and a resistor provided between the MOS transistor and ground. The MOS transistor is provided so that the constant current flows through it. The voltage generated by the voltage divider circuit dividing the reference voltage is input to the non-inverting input terminal of the operational amplifier. One end of the resistor on the MOS transistor side is connected to the inverting input terminal of the operational amplifier. The adjustment circuit adjusts the constant current by changing the voltage division ratio of the reference voltage in the voltage divider circuit. The current source circuit according to claim 1.

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