Temperature compensation circuit

Abstract

To provide a temperature compensation circuit capable of easily changing a temperature coefficient.SOLUTION: A temperature-dependent current generating circuit includes a temperature-dependent element having electrical characteristics that depend on temperature, and generates a plurality of temperature-dependent currents whose levels change in response to the temperature of the temperature-dependent element and whose ratios of level change to temperature change are different. A plurality of current-to-voltage converting circuits generate a plurality of temperature-dependent voltages based on the plurality of temperature-dependent currents, respectively.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature compensation circuit. [Background technology]

[0002] A high-frequency module that includes multiple amplifier circuits and is capable of performing highly accurate temperature compensation is known (Patent Document 1). The temperature compensation circuit disclosed in Patent Document 1 includes a constant current source that generates a constant current that is independent of temperature, and an adjustment current generation circuit that generates an adjustment current having temperature dependency. The adjustment current generated by the adjustment current generation circuit is extracted from the constant current generated by the constant current generation circuit, and the remaining current is converted into a voltage by a current-voltage conversion circuit. This generates a voltage having temperature dependency. A voltage having temperature characteristics is applied to a bias circuit of the amplifier circuit, so that a bias is applied to compensate for the temperature characteristics of the amplifier circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-93408 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to perform appropriate temperature compensation according to the temperature characteristics of an amplifier circuit, the temperature coefficient (the ratio of the change in current or voltage to the change in temperature) must be changed according to the temperature characteristics of the amplifier circuit to be temperature compensated. An object of the present invention is to provide a temperature compensation circuit that can easily change the temperature coefficient. [Means for solving the problem]

[0005] According to one aspect of the present invention, a temperature dependent current generating circuit including a temperature dependent element having electrical characteristics that depend on temperature, the level of which changes according to the temperature of the temperature dependent element, and which generates a plurality of temperature dependent currents having different ratios of level change to temperature change; a plurality of current-voltage conversion circuits for generating a plurality of temperature-dependent voltages based on the plurality of temperature-dependent currents, respectively; A temperature compensation circuit is provided, comprising: Effect of the Invention

[0006] It is possible to select a temperature-dependent current having an appropriate temperature coefficient according to the temperature characteristics of the object to be temperature compensated from among a plurality of temperature-dependent currents having different ratios of level change to temperature change (temperature coefficients).In this way, it becomes possible to easily change the temperature coefficient of the temperature-dependent current used for actual temperature compensation. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram of a temperature compensation circuit according to a first embodiment. [Diagram 2] FIG. 2 is a schematic equivalent circuit diagram of one current-voltage conversion circuit of the temperature compensation circuit according to the first embodiment. [Diagram 3] FIG. 3 is a schematic equivalent circuit diagram of the temperature dependent current generating circuit of the temperature compensation circuit according to the first embodiment. [Figure 4] FIG. 4 is a schematic equivalent circuit diagram of the voltage-current conversion circuit and the N-fold current mirror of the temperature compensation circuit according to the first embodiment. [Diagram 5] FIG. 5 is a block diagram of a temperature compensation circuit according to the second embodiment. [Figure 6] FIG. 6 is a schematic equivalent circuit diagram of a temperature dependent current generating circuit of a temperature compensation circuit according to the second embodiment. [Figure 7] FIG. 7 is a schematic equivalent circuit diagram of the high-frequency amplifier according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First Example] A temperature compensation circuit according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a block diagram of a temperature compensation circuit according to a first embodiment. A temperature-dependent current generating circuit 20 includes a temperature-dependent element 10 having electrical characteristics that depend on temperature. The temperature-dependent element 10 is, for example, a diode whose forward voltage changes depending on temperature. The temperature-dependent current generating circuit 20 generates a plurality of temperature-dependent currents I T Generates multiple temperature-dependent currents I T Each of the temperature-dependent currents I T The ratio of the level change to the temperature change of the temperature dependent element 10 differs between the two.

[0009] Multiple temperature dependent currents I T are input to the current-voltage conversion circuit 30. The current-voltage conversion circuit 30 converts the input temperature-dependent currents I T , the temperature dependent voltage V T and converts it into a temperature dependent voltage V T Generate.

[0010] A plurality of current-voltage conversion circuits 30 are connected to a plurality of input nodes of each of the plurality of second selection circuits 40. A plurality of temperature-dependent voltages V T is input to the second selection circuit 40. The second selection circuit 40 selects one of the current-voltage conversion circuits 30 in response to a second selection signal sel2 input from the outside, and outputs the temperature-dependent voltage V T Output.

[0011] The temperature dependent voltages V T are input to a plurality of voltage-current conversion circuits 50. The voltage-current conversion circuits 50 convert the input temperature-dependent voltage V T current I T1 Convert to current I T1The N-fold current mirror 60 outputs the current I T1 The level of is multiplied by N, and the multiplied current I T2 Output.

[0012] Next, the configuration of the current-voltage conversion circuit 30 will be described with reference to Fig. 2. Fig. 2 is a schematic equivalent circuit diagram of one current-voltage conversion circuit 30. The other current-voltage conversion circuits 30 also have the same configuration as the current-voltage conversion circuit 30 shown in Fig. 2.

[0013] The current-voltage conversion circuit 30 includes a resistor multistage connection circuit 31 and a first selection circuit 32. The resistor multistage connection circuit 31 includes a plurality of resistor elements 31R connected in multiple stages. T One of the temperature-dependent currents I T is input to a resistor multistage connection circuit 31 of one current-voltage conversion circuit 30. An interconnection point of a plurality of resistor elements 31R of the resistor multistage connection circuit 31 is referred to as a voltage extraction node 31N.

[0014] The first selection circuit 32 selects one of the plurality of voltage extraction nodes 31N in response to a first selection signal sel1 input from the outside, and converts the voltage of the selected voltage extraction node 31N into a temperature dependent voltage V T The output is as follows:

[0015] Next, the configuration of the temperature-dependent current generating circuit 20 will be described with reference to Fig. 3. Fig. 3 is a schematic equivalent circuit diagram of the temperature-dependent current generating circuit 20. The temperature-dependent current generating circuit 20 includes a first current generating circuit 21, a second current generating circuit 22, a plurality of third current generating circuits 23, a plurality of fourth current generating circuits 24, a combining circuit 25, and a plurality of output nodes 26.

[0016] The first current generating circuit 21 is a constant current source including an operational amplifier 21A, a p-channel MOSFET 21B, and a resistor 21C. A battery voltage VBAT is applied to the source of the p-channel MOSFET 21B. The first current generating circuit 21 generates a first current I determined by a reference voltage Vref1 applied to one input node of the operational amplifier 21A and the resistance value of the resistor 21C. 1 Generate.

[0017] The second current generating circuit 22 is a current source composed of an operational amplifier 22A, a p-channel MOSFET 22B, a resistor element 22C, and a temperature dependent element 10. The temperature dependent element 10 is, for example, a diode, and its forward voltage changes depending on the temperature. A battery voltage VBAT is applied to the source of the p-channel MOSFET 22B. The second current generating circuit 22 generates a second current I 2 Generate.

[0018] Each of the third current generating circuits 23 includes a p-channel MOSFET and configures a current mirror together with the first current generating circuit 21. Each of the third current generating circuits 23 generates the first current I 1 is used as the reference current and the third current I 3 The third current I 3 The level of the first current I 1 is proportional to the level of the temperature dependent element 10 and is constant regardless of the temperature of the temperature dependent element 10.

[0019] Each of the fourth current generating circuits 24 includes a p-channel MOSFET and configures a current mirror together with the second current generating circuit 22. Each of the fourth current generating circuits 24 generates a second current I 2 is used as the reference current and the fourth current I 4 The fourth current I 4 The level of the second current I 2 and varies depending on the temperature of the temperature dependent element 10.

[0020] The synthesis circuit 25 is connected to some of the third current generating circuits 23 and the fourth current generating circuits 24, and generates a third current I 3 and the fourth current I 4 , and a temperature dependent current I T The ratio between the number of third current generating circuits 23 and the number of fourth current generating circuits 24 connected to each of the plurality of output nodes 26 differs among the plurality of output nodes 26.

[0021] For example, the temperature-dependent current generating circuit 20 includes ten third current generating circuits 23, ten fourth current generating circuits 24, and five output nodes 26. The first output node 26 is connected to four third current generating circuits 23 by the combining circuit 25, the second output node 26 is connected to three third current generating circuits 23 and one fourth current generating circuit 24, the third output node 26 is connected to two third current generating circuits 23 and two fourth current generating circuits 24, the fourth output node 26 is connected to one third current generating circuit 23 and three fourth current generating circuits 24, and the fifth output node 26 is connected to four fourth current generating circuits 24.

[0022] The temperature dependent current I T The levels are shown in the table below. [Table 1]

[0023] Multiple temperature dependent currents I T The third current I 3 The level of the fourth current I 4 The level of the temperature-dependent current I varies depending on the temperature of the temperature-dependent element 10. Therefore, the temperature-dependent current I varies between the multiple output nodes 26 depending on the temperature change of the temperature-dependent element 10. T The ratio of change in the levels is different.

[0024] Next, the configurations of the voltage-current conversion circuit 50 and the N-fold current mirror 60 will be described with reference to Fig. 4. Fig. 4 is a schematic equivalent circuit diagram of the voltage-current conversion circuit 50 and the N-fold current mirror 60.

[0025] The voltage-to-current conversion circuit 50 includes a current source configured with an operational amplifier 51, an n-channel MOSFET 52, and a variable resistance element 53. The temperature dependent voltage V T This current source is connected to the temperature dependent voltage V T and the resistance value of the variable resistance element 53. T1 Generate.

[0026] The resistance value of the variable resistance element 53 is set by a first control signal cnt1 applied from the outside. By changing the resistance value of the variable resistance element 53, the temperature dependent voltage V T from current I T1 The conversion factor to can be adjusted.

[0027] The N-fold current mirror 60 includes p-channel MOSFETs 61, 62, 63, and an operational amplifier 64. The p-channel MOSFET 62 is connected in series to the p-channel MOSFET 61. A battery voltage VBAT is applied to the sources of the p-channel MOSFETs 61 and 63, and the gates of the p-channel MOSFETs 61 and 63 are shorted together. The drains of the p-channel MOSFETs 61 and 63 are connected to two input nodes of the operational amplifier 64, respectively. The output node of the operational amplifier 64 is connected to the gate of the p-channel MOSFET 62. The drain of the p-channel MOSFET 62 is connected to the voltage-current conversion circuit 50 and is also connected to the gates of the p-channel MOSFETs 61 and 63. The p-channel MOSFET 62 has a function of adjusting the on-resistance of the p-channel MOSFET 61.

[0028] The N-fold current mirror 60 outputs the current I T1 is used as the reference current, and the current I T2 Output.

[0029] Next, the excellent effects of the first embodiment will be described. In the first embodiment, a plurality of temperature dependent voltages V T The second selection circuit 40 generates a temperature dependent voltage V T , multiple temperature dependent voltages V T Therefore, in the temperature compensation circuit according to the first embodiment, the temperature coefficient can be easily adjusted. This makes it possible to easily perform appropriate temperature compensation.

[0030] In the first embodiment, the resistor multistage connection circuit 31 and the first selection circuit 32 (FIG. 2) generate a temperature-dependent current I T to temperature dependent voltage V T The temperature dependent voltage V T The temperature dependent voltage V T By selecting the voltage extraction node 31N from among a plurality of voltage extraction nodes 31N, it is easy to T Calibration can be performed.

[0031] Temperature dependent current I T is received by the resistor multistage connection circuit 31, the temperature dependent voltage V T Therefore, for example, the area of ​​the current-voltage conversion circuit 30 can be reduced compared to a case where a current-voltage conversion circuit is configured using MOS transistors.

[0032] By changing the resistance value of the variable resistor element 53 of the voltage-to-current conversion circuit 50 (FIG. 4), the temperature dependent voltage V T from current I T1 This adjusts the conversion coefficient to convert to the current I T1 The decrease in accuracy is suppressed.

[0033] Next, a modification of the first embodiment will be described. In the first embodiment, a plurality of circuits each consisting of a second selection circuit 40, a voltage-current conversion circuit 50, and an N-fold current mirror 60 are provided. T2 It is only necessary to provide a circuit made up of the second selection circuit 40, the voltage-current conversion circuit 50, and the N-fold current mirror 60 in the required number as shown in FIG.

[0034] In the first embodiment, ten third current generating circuits 23 (FIG. 3) and ten fourth current generating circuits 24 (FIG. 3) are provided, but the number of these circuits may be other than ten. In addition, the total number of third current generating circuits 23 and fourth current generating circuits 24 connected to each output node 26 (FIG. 3) is four, but other numbers may be used. It is preferable that the total number of third current generating circuits 23 and fourth current generating circuits 24 connected between multiple output nodes 26 is the same.

[0035] [Second Example] Next, a temperature compensation circuit according to a second embodiment will be described with reference to Fig. 5 and Fig. 6. Below, a description of the configuration common to the temperature compensation circuit according to the first embodiment described with reference to Figs. 1 to 4 will be omitted.

[0036] 5 is a block diagram of a temperature compensation circuit according to a second embodiment. In the second embodiment, the second selection circuit 40 of the temperature compensation circuit according to the first embodiment (FIG. 1) is not provided, and the temperature dependent voltage V T is directly input to the voltage-current conversion circuit 50. In the second embodiment, the function of the second selection circuit 40 of the temperature compensation circuit according to the first embodiment is realized by a temperature-dependent current generation circuit 20 as will be described with reference to FIG.

[0037] 6 is a schematic equivalent circuit diagram of the temperature-dependent current generating circuit 20. As in the first embodiment (FIG. 3), the first current generating circuit 21 generates the temperature-independent first current I 1 The second current generating circuit 22 generates a second current I 2Each of the plurality of fifth current generating circuits 27 has a p-channel MOSFET 27B. The source of the p-channel MOSFET 27B is connected to the battery voltage VBAT, and the gate is connected to one of the gates of the p-channel MOSFET 21B of the first current generating circuit 21 and the p-channel MOSFET 22B of the second current generating circuit 22 via the switch 28.

[0038] A plurality of fifth current generating circuits 27 form a current mirror with one of the first current generating circuit 21 and the second current generating circuit 22 selected by the switch 28. The fifth current generating circuit 27 mirrors the first current I 1 Alternatively, the second current I generated by the second current generating circuit 22 2 is used as the reference current and the fifth current I 5 The fifth current I 5 The level of the first current I 1 or the second current I 2 is proportional to the level of

[0039] That is, the switch 28 selects one of the first current generating circuit 21 and the second current generating circuit 22 as a current source on the reference current side that configures a current mirror with each of the multiple fifth current generating circuits 27. The switching of the switch 28 is performed by a second control signal cnt2 applied from the outside.

[0040] A combiner circuit 25 bundles the drains of a plurality of, for example, four p-channel MOSFETs and connects them to a plurality of output nodes 26. The plurality of output nodes 26 are respectively connected to a plurality of current-voltage conversion circuits 30. This generates a plurality of fifth currents I 5 are summed together to output a temperature dependent current I T will be output as:

[0041] Next, the advantageous effects of the second embodiment will be described. In the second embodiment, when the switch 28 is switched between the first current generating circuit 21 and the second current generating circuit 22, a temperature dependent current I T The first current I 1 and the second current I 2 This allows the ratio of the temperature dependent current I T The ratio of change in the levels of the output nodes 26 can be adjusted for each output node 26.

[0042] [Third Example] Next, a high frequency amplifier according to a third embodiment will be described with reference to FIG. 7. The high frequency amplifier according to the third embodiment includes the temperature compensation circuit according to the first or second embodiment.

[0043] 7 is a schematic equivalent circuit diagram of a high frequency amplifier according to the third embodiment. The emitter of a power amplifier transistor 90 is grounded, a power supply voltage Vcc is applied to the collector via a choke coil 91, and a high frequency signal RFin is input to the base via a DC cut capacitor 92. For example, a heterojunction bipolar transistor is used as the power amplifier transistor 90. An amplified high frequency signal RFout is output from the collector of the power amplifier transistor 90.

[0044] A bias current Ibb is supplied from the bias circuit 80 to the base of the power amplification transistor 90. The bias circuit 80 includes a bias transistor 81, a resistor element 82, and a diode circuit 83. The bias transistor 81 is, for example, a heterojunction bipolar transistor. The diode circuit 83 is formed of a series-connected circuit of two diode-connected bipolar transistors.

[0045] The emitter of the biasing transistor 81 is connected to the base of the power amplifying transistor 90 , and a bias current Ibb is supplied from the emitter of the biasing transistor 81 to the base of the power amplifying transistor 90 .

[0046] A bias power supply current IeC output from the temperature compensation circuit 70 is supplied to the collector of the bias transistor 81, and a bias control current IB is supplied to the base of the bias transistor 81 via a resistor element 82. A part of the bias control current IB flows to ground via a diode circuit 83.

[0047] The bias power supply current IeC and the bias control current IB are currents I whose levels change depending on the temperature of the temperature dependent element 10. T2 (corresponding to FIG. 1 and FIG. 5). The temperature dependent element 10 is provided at a location where the temperature change of the power amplifying transistor 90 is reflected.

[0048] Next, the excellent effects of the third embodiment will be described. In the third embodiment, the temperature of the temperature dependent element 10 rises due to a temperature rise of the power amplifier transistor 90. As a result, the temperature rise of the power amplifier transistor 90 is reflected in the bias power supply current IeC and the bias control current IB. The fluctuation in characteristics caused by the temperature rise of the power amplifier transistor 90 can be counteracted by adjusting the levels of the bias power supply current IeC and the bias control current IB.

[0049] When the temperature compensation circuit according to the first embodiment (FIG. 1) is used, the second selection circuit 40 (FIG. 1) selects a temperature dependent voltage V T By selecting the above, appropriate temperature compensation can be performed. When the temperature compensation circuit according to the second embodiment (FIGS. 5 and 6) is used, appropriate temperature compensation can be performed by switching the switch 28 in accordance with the temperature characteristics of the power amplification transistor 90.

[0050] The above-mentioned embodiments are merely examples, and it goes without saying that partial replacement or combination of the configurations shown in different embodiments is possible. Similar effects due to similar configurations of multiple embodiments are not mentioned in each embodiment. Furthermore, the present invention is not limited to the above-mentioned embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible. [Explanation of symbols]

[0051] 10 Temperature dependent elements 20 Temperature dependent current generation circuit 21 1st current generation circuit 21A Op Amp 21B p-channel MOSFET 21C Resistance element 22 2nd current generation circuit 22A Op Amp 22B p-channel MOSFET 22C Resistance element 23 Third current generation circuit 24 4th current generation circuit 25 Synthesis circuit 26 Output Nodes 27 5th current generation circuit 28 Switch 30 Current-to-voltage conversion circuit 31 Resistor multi-stage connection circuit 31N Voltage take-off node 31R Resistor element 32 First selection circuit 40 Second selection circuit 50 Voltage-to-current conversion circuit 51 Operational Amplifiers 52 Transistor 53 Variable resistance element 60 N-fold current mirror 61, 62, 63 n-channel MOSFETs 64 Op-amps 70 Temperature compensation circuit 80 Bias Circuit 81 Bias transistor 82 Resistance element 83 Diode Circuit 90 Power Amplification Transistor 91 Choke coil 92 DC cut capacitor

Claims

1. a temperature dependent current generating circuit including a temperature dependent element having electrical characteristics that depend on temperature, the level of which changes according to the temperature of the temperature dependent element, and which generates a plurality of temperature dependent currents having different ratios of level change to temperature change; a plurality of current-voltage conversion circuits for generating a plurality of temperature-dependent voltages based on the plurality of temperature-dependent currents, respectively; A temperature compensation circuit with

2. Each of the plurality of current-voltage conversion circuits a plurality of resistor multi-stage connection circuits to which the plurality of temperature dependent currents are respectively input; a plurality of first selection circuits connected to the plurality of resistor multi-stage connection circuits, respectively; Including, each of the plurality of resistor multi-stage connection circuits includes a plurality of resistor elements connected in multiple stages; 2. The temperature compensation circuit according to claim 1, wherein each of the plurality of first selection circuits selects one from among voltage extraction nodes which are interconnection points of a plurality of resistive elements in a connected resistive multi-stage connection circuit, and outputs the voltage of the selected voltage extraction node as the temperature-dependent voltage.

3. The temperature dependent current generating circuit comprises: a first current generating circuit that generates a first current that is independent of the temperature of the temperature dependent element; a second current generating circuit that generates a second current that depends on a temperature of the temperature dependent element; a plurality of third current generating circuits that configure a current mirror together with the first current generating circuit and output a plurality of third currents using the first current as a reference current; a plurality of fourth current generating circuits that configure a current mirror together with the second current generating circuit and output a plurality of fourth currents using the second current as a reference current; a combining circuit connected to the plurality of third current generating circuits and the plurality of fourth current generating circuits, the combining circuit adding up the third current and the fourth current and outputting the sum as the temperature dependent current from each of a plurality of output nodes; Including, 3. The temperature compensation circuit according to claim 1, wherein a ratio between the number of the third current generating circuits and the number of the fourth current generating circuits connected to each of the plurality of output nodes is different between the plurality of output nodes.

4. 4. The temperature compensation circuit according to claim 3, further comprising a voltage-to-current conversion circuit that converts the temperature dependent voltage generated by at least one of the plurality of current-to-voltage conversion circuits into a current.

5. 5. The temperature compensation circuit according to claim 4, further comprising a second selection circuit that selects one of the plurality of current-voltage conversion circuits and inputs the temperature dependent voltage output from the selected current-voltage conversion circuit to the voltage-current conversion circuit.

6. The temperature dependent current generating circuit comprises: a first current generating circuit that generates a first current that is independent of the temperature of the temperature dependent element; a second current generating circuit that generates a second current that depends on a temperature of the temperature dependent element; a plurality of fifth current generating circuits each forming a current mirror with one of the first current generating circuit and the second current generating circuit, and each outputting a fifth current using the first current or the second current as a reference current; a plurality of switches for selecting one of the first current generating circuit and the second current generating circuit as a current source on a reference current side that configures a current mirror with each of the plurality of fifth current generating circuits; a synthesis circuit connected to some of the plurality of fifth current generating circuits, which sums the fifth currents and outputs the sum as the temperature-dependent current from each of a plurality of output nodes; 3. The temperature compensation circuit according to claim 1, further comprising:

7. 7. The temperature compensation circuit according to claim 6, further comprising a voltage-to-current conversion circuit that converts the temperature dependent voltage generated by at least one of the plurality of current-to-voltage conversion circuits into a current.

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