CN116346113B - High-precision current-controlled load switch circuit and trimming method thereof - Google Patents
High-precision current-controlled load switch circuit and trimming method thereof Download PDFInfo
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- CN116346113B CN116346113B CN202310584648.7A CN202310584648A CN116346113B CN 116346113 B CN116346113 B CN 116346113B CN 202310584648 A CN202310584648 A CN 202310584648A CN 116346113 B CN116346113 B CN 116346113B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
- H03K17/08104—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in field-effect transistor switches
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/16—Modifications for eliminating interference voltages or currents
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Abstract
The application provides a high-precision current-controlled load switch circuit and a trimming method thereof, wherein the circuit comprises a first switch tube, a second switch tube, an error adjusting unit, a first resistor, a second resistor and a threshold trimming circuit; the difference value between the gate source voltage and the on threshold voltage of the first switching tube is controlled to be equal to the difference value between the gate source voltage and the on threshold voltage of the second switching tube through adjustment of the first resistor, the second resistor, the threshold trimming circuit and the error adjusting unit; the trimming method comprises the following steps: testing whether the conduction threshold voltages of the first switching tube and the second switching tube are equal; when the conducting threshold voltage of the first switching tube is smaller, the value of the trimming current is reduced; when the conduction threshold voltage of the first switching tube is larger, the value of the trimming current is increased. The on-resistance of the first switching tube and the on-resistance of the second switching tube are not influenced by process manufacturing, and are only related to the width-to-length ratio of the first switching tube and the second switching tube, so that high-precision control of the load switching circuit is realized.
Description
Technical Field
The application relates to the technical field of integrated load switches, in particular to a high-precision current-controlled load switch circuit and a trimming method thereof.
Background
An integrated load switch is an integrated electronic relay that can be used to turn on and off a power rail. As shown in fig. 1, most base load switches contain four pins: an input voltage pin VIN, an output voltage pin VOUT, an enable pin ON, and a ground pin GND. As shown in fig. 1, when the device is enabled via the ON pin, the integrated load switch internal FET turns ON, causing current to flow from the input pin to the output pin and delivering power to downstream circuitry. In recent years, integrated load switches are beginning to be widely applied to products such as intelligent wearable devices, TWS headphones, NB_IOT, SSD and the like. The integrated load switch has the advantages of small surge current, few peripheral devices, small volume, large input voltage range, few peripheral devices, small leakage current and the like. In the application background that the load has higher and higher requirements on the current control precision, it is very important to improve the output current control precision of the integrated load switch.
For a load switch circuit, the current design emphasis is on improving the control precision of the load switch circuit on the load current. In general, when sampling a current flowing through a load switch, a sampling switch is typically connected in parallel across the load switch to sample the current flowing through the load switch. In general, the on-resistance of the sampling switch and the on-resistance of the load switch are in a K-fold relationship, so that the current flowing through the sampling switch can be indicative of the current flowing through the load switch. The load switch circuit controls the current flowing through the load switch by controlling the current flowing through the sampling switch.
During normal operation, the load switch and the sampling switch are both operated in a linear region, and if the two switching tubes are MOS tubes, the on-resistance Ron of the two MOS tubes is as follows:
wherein mu n C ox As a function of the process parameters,is the width-to-length ratio of the MOS tube, +.>Is the gate-source voltage of MOS tube, +.>Is the on threshold voltage of the MOS tube. When V of sampling switch and load switch GS And V is equal to TH At the same time, their respective on-resistances Ron and their aspect ratios +.>Inversely proportional, and accurate sampling of current is achieved.
However, in the actual manufacturing process of the chip, due to the influence of process deviation, even if sampling switches and load switches of the same device type are selected, the parameters of the chip may deviate. Due to these deviationsAppears to cause the K value to follow V GS And V is equal to TH The larger the deviation between the K value and the desired design value is, the lower the accuracy of the load current control is.
Disclosure of Invention
The present application aims to solve at least one of the technical problems existing in the prior art.
To this end, a first aspect of the present application provides a high precision current controlled load switching circuit.
The second aspect of the application provides a trimming method of a load switch circuit controlled by high-precision current.
The application provides a high-precision current-controlled load switch circuit, which comprises: the first switch tube is provided with a first end, a second end and a control end, wherein the first end of the first switch tube receives an input voltage signal, the second end of the first switch tube provides an output voltage signal, and the control end of the first switch tube receives a driving control signal through a first resistor; the second switch tube is provided with a first end, a second end and a control end, the first end of the second switch tube is coupled with the first end of the first switch tube, the second end of the second switch tube is electrically connected to the ground through a reference current source, and the control end of the second switch tube receives the driving control signal through a second resistor; the error adjusting unit is provided with a first input end, a second input end and an output end, wherein the first input end of the error adjusting unit is coupled with the second end of the first switching tube, the second input end of the error adjusting unit is coupled with the second end of the second switching tube, and the output end of the error adjusting unit is coupled with the control end of the first switching tube; the threshold trimming circuit is provided with a first end and a second end, the first end of the threshold trimming circuit receives a trimming signal, the second end of the threshold trimming circuit is coupled with the control end of the second switch tube and provides trimming current, and the threshold trimming circuit adjusts the value of the trimming current according to the trimming signal.
The high-precision current-controlled load switch circuit according to the technical scheme of the application can also have the following additional technical characteristics:
in the above technical solution, the threshold trimming circuit includes: a first current source; a first current mirror unit having an input and at least two first outputs, the input of the first current mirror unit being coupled to a first current source; the switch array comprises at least two connecting switches, the number of the connecting switches is equal to that of the first output ends of the first current mirror units, the connecting switches are in one-to-one correspondence, each connecting switch is coupled between the corresponding first output end of the first current mirror unit and the second end of the threshold trimming circuit, and the trimming signal is used for controlling the connecting switches to be turned on or turned off.
In the above technical solution, the connection switch includes an electronic switch; the electronic switch is provided with a first end, a second end and a control end, wherein the first end of the electronic switch is coupled with a corresponding first output end in the first current mirror unit, the second end of the electronic switch is coupled with the second end of the threshold trimming circuit, and the control end of the electronic switch is connected with a trimming signal.
In the above technical solution, the connection switch includes a fuse, and the trimming signal is used for blowing out a part of the fuse.
In the above technical solution, the first current mirror unit further has a second output terminal, and the load switch circuit further includes: and the second current mirror unit is provided with an input end and an output end, the input end of the second current mirror unit is coupled with the second output end of the first current mirror unit, and the output end of the second current mirror unit provides the driving control signal.
In the above technical solution, further includes: and a second current mirror unit having an input coupled to ground through a second current source and an output providing the drive control signal.
In the above technical solution, the error adjustment unit includes: the error amplifier is provided with a first input end, a second input end and an output end, wherein the first input end of the error amplifier is coupled with the second end of the first switching tube, and the second input end of the error amplifier is coupled with the second end of the second switching tube; the third switching tube is provided with a first end, a second end and a control end, the control end of the third switching tube is coupled with the output end of the error amplifier, the first end of the third switching tube is coupled with the control end of the first switching tube, and the second end of the third switching tube is electrically connected with the ground.
In the above technical solution, the trimming signal has a fixed initial value.
In the above technical solution, the output end of the error adjusting unit provides a pull-down current signal; and the resistance values of the first resistor and the second resistor are determined according to the fixed initial value of the trimming signal and the value of the pull-down current signal.
The application provides a trimming method of a load switch circuit controlled by high-precision current, which is used for trimming the load switch circuit in any one of the technical schemes, and comprises the steps of testing whether the conduction threshold voltages of a first switch tube and a second switch tube are equal or not by adopting a chip tester;
when the conducting threshold voltage of the first switching tube is smaller, the value of the trimming current is reduced; and
and when the conduction threshold voltage of the first switching tube is larger, increasing the value of the trimming current.
In summary, due to the adoption of the technical characteristics, the application has the beneficial effects that:
the threshold trimming circuit is used for trimming the deviation of the on threshold voltage of the first switching tube and the second switching tube, namely the load switch and the sampling switch, so that the on resistance of the first switching tube and the on resistance of the second switching tube are not influenced by process manufacturing and are only related to the width-to-length ratio of the first switching tube and the second switching tube, and the control precision of the load current in the load switching circuit is improved.
Additional aspects and advantages of the application will be set forth in part in the description which follows, or may be learned by practice of the application.
Drawings
The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a circuit schematic of a conventional load switching circuit;
FIG. 2 is a circuit schematic of a high precision current controlled load switching circuit according to one embodiment of the present application;
FIG. 3 is a circuit schematic of a high precision current controlled load switching circuit according to another embodiment of the present application;
fig. 4 is a circuit schematic of a high precision current controlled load switching circuit according to yet another embodiment of the present application.
Detailed Description
In order that the above-recited objects, features and advantages of the present application will be more clearly understood, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, without conflict, the embodiments of the present application and features in the embodiments may be combined with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced otherwise than as described herein, and therefore the scope of the present application is not limited to the specific embodiments disclosed below. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. The verbs "comprise" and "have" are used herein as open limits, which neither exclude nor require that there be unrecited features. Features recited in the dependent claims may be freely combined with each other unless explicitly stated otherwise. The use of an element defined as "one" or "one" (i.e., in the singular) throughout this document does not exclude the possibility of a plurality of such elements. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Unless otherwise indicated, the terms "connected" and "coupled" are used to designate electrical connections between circuit elements that may be direct or may be via one or more other elements. In contrast, when an element is referred to as being "directly connected to" or "directly coupled to" another element, there are no intervening elements present. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
A load switching circuit for high-precision current control and a trimming method thereof according to some embodiments of the present application are described below with reference to fig. 2 to 4.
Some embodiments of the application provide a high precision current controlled load switching circuit.
The first embodiment of the present application provides a high-precision current-controlled load switch circuit having an input voltage terminal VIN, an output voltage terminal VOUT, an enable terminal ON, and a ground terminal GND. The enable terminal ON of the load switch circuit provides an enable signal for enabling the load switch circuit, in one embodiment, the drive control signal idrv_on will be generated internally of the load switch when the load switch circuit is enabled. The input voltage end VIN of the load switch circuit is used for receiving an input voltage signal, and the output voltage end VOUT of the load switch circuit provides an output voltage signal and is connected with a downstream circuit or a load; the load switching circuit is connected to ground through ground GND. The drive control signal Idrv_on is used for controlling a switching tube in the load switching circuit to be conducted, so that current flows from an input voltage end to an output voltage end of the load switching circuit, and electric energy is transmitted to a downstream circuit or used for load power supply.
Fig. 2 shows a circuit schematic of a high-precision current-controlled load switching circuit, which mainly comprises: the device comprises a first switch tube, a second switch tube, an error adjusting unit, a first resistor, a second resistor and a threshold trimming circuit. The first switching tube and the second switching tube are controllable electronic switching devices, and a metal oxide semiconductor field effect tube (Metal Oxide Semiconductor Field Effect Transistor, MOSFET), a bipolar transistor (Bipolar Junction Transistor, BJT), a junction field effect tube (Junction Field Effect Transistor, JFET), an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) or the like can be selected.
In some embodiments, when the first switching tube adopts a MOS tube, the first end, the second end and the control end of the first switching tube power_mos correspond to the drain electrode, the source electrode and the gate electrode of the MOS tube respectively. That is, the gate of the first switching tube power_mos receives the driving control signal idrv_on through the first resistor R1, the drain of the first switching tube power_mos is coupled to the input voltage terminal VIN of the load switching circuit to receive the input voltage signal, and the source of the first switching tube power_mos is coupled to the load resistor r_load and the output voltage terminal VOUT of the load switching circuit, respectively, to provide the output voltage signal VOUT, where the current flowing through the load resistor r_load is the load current i_load.
When the second switching tube adopts the MOS tube, the first end, the second end and the control end of the second switching tube sense_mos respectively correspond to the grid electrode, the drain electrode and the source electrode of the MOS tube. That is, the gate of the second switching transistor sense_mos receives the driving control signal idrv_on through the second resistor R2, the drain of the second switching transistor sense_mos is coupled to the input voltage terminal VIN of the load switching circuit to receive the input voltage signal, and the source of the second switching transistor sense_mos is electrically connected to ground through the reference current source, wherein the reference current source provides the reference current i_ref. In this embodiment, the first switching tube and the second switching tube are the same type of device, and the width-to-length ratio of the first switching tube power_mos to the width-to-length ratio of the second switching tube sense_mos is 1: k.
The error adjusting unit is provided with a first input end, a second input end and an output end, wherein the first input end of the error adjusting unit is coupled with the source electrode of the first switching tube power_mos and is used for receiving the output voltage signal Vout of the load switching circuit; the second input terminal of the error adjusting unit is coupled to the source of the second switch transistor sense_mos, and receives the voltage signal on the source of the second switch transistor sense_mos, which is schematically shown as the reference voltage signal v_ref. The output end of the error adjusting unit is coupled to the grid electrode of the first switching tube power_mos; the error adjusting unit is used for adjusting the gate voltage VG1 of the first switching tube power_mos according to the comparison result of the output voltage signal Vout of the load switching circuit and the reference voltage signal V_ref. In one embodiment, the error adjustment unit generates a pull-down current signal Isink according to a comparison result of the output voltage signal Vout and the reference voltage signal V_ref, and adjusts the gate voltage VG1 of the first switching tube power_mos through the pull-down current signal Isink.
Specifically, in one embodiment, the error adjustment unit includes an error amplifier EA and a third switching tube M1. The error amplifier EA has a first input, a second input and an output, in one embodiment the first input is an inverting input and the second input is a non-inverting input, the inverting input of the error amplifier EA is coupled to the source of the first switching transistor power_mos, and the non-inverting input of the error amplifier is coupled to the source of the second switching transistor sense_mos. The third switching tube M1 is provided with a first end, a second end and a control end, and when the third switching tube M1 adopts an MOS tube, the first end, the second end and the control end respectively correspond to the drain electrode, the source electrode and the grid electrode of the MOS tube; that is, the gate of the third switching tube M1 is coupled to the output end of the error amplifier EA, the drain of the third switching tube M1 is coupled to the first end of the first switching tube power_mos, and the source of the third switching tube M1 is coupled to the ground. Specifically, the error amplifier EA compares the reference voltage signal v_ref with the output voltage signal Vout, amplifies an error value of the reference voltage signal v_ref and the output voltage signal Vout to output an error signal eao, and the error signal eao is used for adjusting the current flowing through the third switching transistor M1 (i.e., the pull-down current i_sink), thereby adjusting the gate voltage VG1 of the first switching transistor power_mos.
The first resistor and the second resistor may be resistive elements such as a fixed resistor and an adjustable resistor, and in one embodiment, the first resistor is a resistor R1, and the second resistor is a resistor R2. In one embodiment, the drive control signal idrv_on is generated by a drive circuit, the drive control signal idrv_on comprising a current signal. In one embodiment, the drive control signal idrv_on is generated by enabling the drive circuit at the enable terminal ON of the load switching circuit.
The threshold trimming circuit is provided with a first end and a second end, the first end of the threshold trimming circuit is connected with a trimming signal Trim, the second end of the threshold trimming circuit is coupled with the grid electrode of the second switching tube, the threshold trimming circuit generates a trimming current I_trim according to the trimming signal Trim, and the grid voltage VG2 of the second switching tube sense_mos is adjusted by changing the size of the trimming current I_trim.
Since the first switching transistor power_mos and the second switching transistor sense_mos are devices of the same type, the on threshold voltage V of the first switching transistor power_mos and the second switching transistor sense_mos is equal to the on threshold voltage V of the second switching transistor sense_mos in the case of ideal matching TH Equal, but deviations in the parameter values may occur during the manufacturing process, resulting in non-identical final physical realization values. In the present embodiment, the gate-source voltage V of the first switching transistor power_mos is controlled by the adjustment of the first resistor R1, the second resistor R2, the threshold trimming circuit and the error adjusting unit GS1 And turn-on threshold voltage V TH1 Is the difference (V) GS1 - V TH1 ) With the gate-source voltage V of the second switching tube GS2 And turn-on threshold voltage V TH2 Is the difference (V) GS2 - V TH2 ) The on-state resistance Ron_power of the first switching tube and the on-state resistance Ron_sense of the second switching tube are equal, and are not influenced by process manufacturing, and are only related to the width-to-length ratio of the first switching tube and the second switching tube. When the width-to-length ratio of the first switching tube to the second switching tube is equal to 1: at K, the on-resistance is also K times the relationship, namely: ron_power=k×ron_sense.
In addition, when the driving control signal idrv_on is a current signal, the value of the driving control signal idrv_on has the following relationship with the trimming current i_trim and the pull-down current i_sink: i_drv-on=i_sink+i_trim. When the threshold trimming circuit does not trim, the trimming current i_trim is a fixed initial value, and the gate voltage VG1 of the first switching transistor power_mos and the gate voltage VG2 of the second switching transistor sense_mos are set to be equal. Since vg1=vg2, after the first switching tube power_mos is turned on with the second switching tube sense_mos, the relationship between the first resistor R1 and the second resistor R2 satisfies the equation: i_trim×r1=i_sink×r2. Therefore, in one embodiment, the resistance of the first resistor R1 is N times that of the second resistor R2, and the specific value of N can be set according to the fixed initial value of the trimming current i_trim and the value of the pull-down current i_sink.
FIG. 3 is a further embodiment according to the applicationA schematic circuit diagram illustrating a threshold trimming circuit in a high precision current controlled load switching circuit, the threshold trimming circuit comprising: a first current source, a first current mirror unit, and a switch array. Wherein the first current source is used for generating a base current Ibase1; the first current mirror unit has an input and at least two outputs. The input end of the first current mirror unit is coupled with a first current source; the first current mirror unit may employ a conventional current mirror structure, such as a fourth switching tube (e.g., M2 1 ，M2 2 ，…，M2 5 ) The gates of the fourth switching tubes are coupled in parallel to the first current source, the sources of the fourth switching tubes are coupled in parallel to the ground, wherein one of the fourth switching tubes (e.g. M2 1 ) Is connected to the first current source, the remaining fourth switching tubes (e.g. M2 2 ，…，M2 5 ) The drain electrode of the first current mirror unit is the output end of the first current mirror unit, the first current mirror unit forms output current at the output end of the first current mirror unit by mirroring the basic current Ibase1, and the current of each output end of the first current mirror unit can be regulated by setting the width-to-length ratio of each fourth switching tube in the first current mirror unit; it will be appreciated that a person skilled in the art may choose a current mirror with a different structure than the above, as long as it is ensured that the first current mirror unit is capable of outputting at least two stable currents. It is to be understood that the first current mirror unit in fig. 3 is schematically comprised of five fourth switching tubes (M2 1 ，M2 2 ，…，M2 5 ) This is not a limitation of the present application, and in other embodiments the first current mirror unit may comprise any number of fourth switching tubes.
In one embodiment, the switch array includes at least two connection switches, the number of the connection switches is equal to that of the output ends of the first current mirror units, and the connection switches are in one-to-one correspondence, each connection switch is coupled between the output end of the corresponding first current mirror unit and the second end of the threshold trimming circuit, and the trimming signal Trim is used for controlling the connection switches to be turned on or off so as to adjust the trimming current I_trim of the second end of the threshold trimming circuit.
In one embodiment, the switch array has a control terminal, and the control terminal of the switch array is connected to the trimming signal Trim, where the trimming signal Trim may be provided by an external chip tester, or the external chip tester may give an instruction signal to send the trimming signal Trim that is originally stored in the chip memory to the switch array. In one embodiment, the trimming signal Trim is a set of discrete high-low level signals for directly or indirectly controlling the on-off of the connection switches in the switch array, and specifically, the trimming signal Trim is used for indicating the plurality of connection switches in the switch array to perform different switch combinations, and each switch combination corresponds to one trimming current. As shown in fig. 3, the switch array includes four connection switches S1, S2, S3, S4, the four output ends of the first current mirror unit output currents I1, I2, I3, I4, one ends of the connection switches S1, S2, S3, S4 are respectively connected with the four output ends of the first current mirror unit in a one-to-one correspondence manner, and the other ends of the connection switches S1, S2, S3, S4 are coupled to the gate of the second switching transistor sense_mos. In one embodiment, one of the connection switches (e.g. S4) is set to a normally-on initial state, the other connection switches (e.g. S1, S2 and S3) are set to a normally-off initial state, and the output current (e.g. I4) of the normally-on connection switch is a fixed initial value of the trimming current i_trim. In other embodiments, other switches, such as switch S3, may be provided, and the other connection switches (e.g. S1, S2, and S4) are in a normally-on state, and the output current I3 is a fixed initial value of the trimming current i_trim. And the trimming signal Trim controls other switches except the normally-on connecting switch to conduct on or off selection, so that the value of the trimming current I_trim is adjusted.
In one embodiment, the connection switch may be a reusable electronic switch or a disposable electronic switch. Such as one-time programmable logic switches (OTP), re-programmable logic switches (MTP), electronic fuses (e-fuses), and the like. In these embodiments, the electronic switch has a first end, a second end and a control end, the first end of the electronic switch is coupled to the output end of the first current mirror unit, the second end of the electronic switch is coupled to the second end of the threshold trimming circuit, and the control end of the electronic switch is connected to the trimming signal Trim.
In other embodiments, the connection switch includes a fuse, and the trimming signal Trim controls the current value applied across the fuse, thereby enabling one-time adjustment of the trimming current by blowing or not blowing the fuse.
In the embodiment shown in fig. 3, the driving signal generating module is further included for generating the driving control signal idrv_on. In an embodiment, the drive control signal idrv_on is generated by a second current mirror unit and a second current source for generating the base current Ibase2. In yet another embodiment, in order to make the current control of the load switching circuit more accurate, the base current Ibase1 and the base current Ibase2 may be generated by the same current source, so that errors or mismatches occurring between different current sources may be avoided, and the current regulation accuracy of the load switching circuit may be improved as much as possible. As shown in the embodiment of fig. 4, the output end of the first current mirror unit is divided into a plurality of first output ends and second output ends, and the plurality of first output ends of the first current mirror unit are respectively connected with the connecting switches in the switch array in a one-to-one correspondence manner, and the number of the connecting switches is equal to that of the first output ends of the first current mirror unit. The input end of the second current mirror unit is coupled with the second output end of the first current mirror unit, and the output end of the second current mirror unit is coupled with the control end of the first switching tube power_mos and the control end of the second switching tube sense_mos through a first resistor R1 and a second resistor R2 respectively. In particular, the second current mirror unit may employ a conventional current mirror structure, such as a fifth switching tube (e.g., M3 1 And M3 2 ) The gates of the two fifth switching transistors are connected in parallel to the second output terminal (e.g. M2 2 The drains of (a) and (b) the sources of the fifth switching tubes receive the charge pump supply voltage CP, one of the fifth switching tubes (e.g., M3 1 ) Is connected to the second output terminal of the first current mirror unit, another fifth switching tube (e.g. M3 2 ) The drain electrode of the second current mirror unit is the output end of the second current mirror unit.
In some embodiments, the load switching circuit further has an over-current detection module (not shown in the figure) that receives a current signal indicative of the flow of current through the load switching circuit, and if the current signal exceeds a set threshold value, indicating that the load switching circuit is over-current, forcibly pulls down the gate voltage of the first switching tube by a pull-down switch provided at the gate of the first switching tube, thereby turning off the first switching tube.
Some embodiments of the present application provide a trimming method for a load switch circuit controlled by high-precision current, which trims the load switch circuit according to any one of the embodiments, and includes the following steps: and testing whether the conduction threshold voltages of the first switching tube power_mos and the second switching tube sense_mos are equal or not by adopting a chip tester. The first switching tube power_mos and the second switching tube sense_mos are devices of the same type, and in the case of ideal matching, the first switching tube power_mos and the second switching tube sense_mos conduct the threshold voltage V TH Equal, but deviations in the parameter values may occur during the manufacturing process, resulting in non-identical final physical realization values. As will be appreciated by those skilled in the art, the chip tester may test for deviations in the turn-on threshold, for example, by observing deviations in the turn-on threshold voltage from the measured current waveform, and confirming whether the deviation is caused by the first switching transistor power_mos or the deviation is caused by the second switching transistor sense_mos.
When the mismatch of the conduction threshold voltage is detected and the deviation is determined to be the conduction threshold voltage V of the first switching tube power_mos TH1 If the voltage is smaller, a proper trimming signal Trim is selected to reduce the value of the trimming current I_trim through a threshold trimming circuit, so that the gate voltage VG2 of the second switching tube sense_mos is increased to ensure V GS2 - V TH2 = V GS1 - V TH1 . Specifically, when trimming the load switch circuit as shown in fig. 3 or fig. 4, to reduce the value of the trimming current i_trim, the normally-on connection switch (e.g. S4) may be selectively turned off, and then the connection switch corresponding to a smaller current than the normally-on connection switch current (e.g. I4) is selected to be turned on according to the deviation degree, so as to reduce the trimming current i_trim. In one embodiment, the current ratio of the first current mirror unit may be set to i1:i2:i3:i4=1:2:3:6。
As another example, when it is detected that the on threshold voltage mismatch occurs, the on threshold voltage V of the first switching transistor power_mos TH1 If the voltage is larger, a proper trimming signal Trim is selected to increase the value of the trimming current I_trim through a threshold trimming circuit, so that the gate voltage VG2 of the second switching tube sense_mos is reduced to ensure V GS2 - V TH2 = V GS1 - V TH1 . Specifically, when trimming the load switch circuit shown in fig. 3 or fig. 4, to increase the value of the trimming current i_trim, the remaining connection switches of the control portion may be turned on according to the degree of deviation to increase the trimming current i_trim. It can be appreciated that the more connection switches are in the on state, the greater the trimming current.
In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. A high precision current controlled load switching circuit, the load switching circuit comprising:
the first switch tube is provided with a first end, a second end and a control end, wherein the first end of the first switch tube receives an input voltage signal, the second end of the first switch tube provides an output voltage signal, and the control end of the first switch tube receives a driving control signal through a first resistor;
the second switch tube is provided with a first end, a second end and a control end, the first end of the second switch tube is coupled with the first end of the first switch tube, the second end of the second switch tube is electrically connected to the ground through a reference current source, and the control end of the second switch tube receives the driving control signal through a second resistor;
the error adjusting unit is provided with a first input end, a second input end and an output end, wherein the first input end of the error adjusting unit is coupled with the second end of the first switching tube, the second input end of the error adjusting unit is coupled with the second end of the second switching tube, and the output end of the error adjusting unit is coupled with the control end of the first switching tube; and
the threshold trimming circuit is provided with a first end and a second end, the first end of the threshold trimming circuit receives a trimming signal, the second end of the threshold trimming circuit is coupled with the control end of the second switch tube and provides trimming current, and the threshold trimming circuit adjusts the value of the trimming current according to the trimming signal.
2. The high precision current controlled load switching circuit of claim 1, wherein the threshold trimming circuit comprises:
a first current source;
a first current mirror unit having an input and at least two first outputs, the input of the first current mirror unit being coupled to a first current source; and
the switch array comprises at least two connecting switches, the number of the connecting switches is equal to that of the first output ends of the first current mirror units, the connecting switches are in one-to-one correspondence, each connecting switch is coupled between the corresponding first output end of the first current mirror unit and the second end of the threshold trimming circuit, and the trimming signal is used for controlling the connecting switches to be turned on or turned off.
3. The high precision current controlled load switching circuit of claim 2 wherein the connection switch comprises an electronic switch;
the electronic switch is provided with a first end, a second end and a control end, wherein the first end of the electronic switch is coupled with a corresponding first output end in the first current mirror unit, the second end of the electronic switch is coupled with the second end of the threshold trimming circuit, and the control end of the electronic switch is connected with a trimming signal.
4. The high precision current controlled load switching circuit of claim 2 wherein the connection switch comprises a fuse, and wherein the trimming signal is used to blow a portion of the fuse.
5. The high precision current controlled load switching circuit of claim 2 wherein the first current mirror unit further has a second output, the load switching circuit further comprising:
and the second current mirror unit is provided with an input end and an output end, the input end of the second current mirror unit is coupled with the second output end of the first current mirror unit, and the output end of the second current mirror unit provides the driving control signal.
6. The high precision current controlled load switching circuit of claim 2, further comprising:
and a second current mirror unit having an input coupled to ground through a second current source and an output providing the drive control signal.
7. The high-precision current-controlled load switching circuit according to claim 1, wherein the error adjustment unit includes:
the error amplifier is provided with a first input end, a second input end and an output end, wherein the first input end of the error amplifier is coupled with the second end of the first switching tube, and the second input end of the error amplifier is coupled with the second end of the second switching tube;
the third switching tube is provided with a first end, a second end and a control end, the control end of the third switching tube is coupled with the output end of the error amplifier, the first end of the third switching tube is coupled with the control end of the first switching tube, and the second end of the third switching tube is electrically connected with the ground.
8. The high precision current controlled load switching circuit of claim 1 wherein the trimming signal has a fixed initial value.
9. The high precision current controlled load switching circuit of claim 8, wherein the output of the error adjustment unit provides a pull-down current signal; and the resistance values of the first resistor and the second resistor are determined according to the fixed initial value of the trimming signal and the value of the pull-down current signal.
10. A trimming method for a high-precision current-controlled load switching circuit according to any one of claims 1 to 9, comprising:
testing whether the conduction threshold voltages of the first switching tube and the second switching tube are equal or not by adopting a chip tester;
when the conducting threshold voltage of the first switching tube is smaller, the value of the trimming current is reduced; and
and when the conduction threshold voltage of the first switching tube is larger, increasing the value of the trimming current.
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| CN202310584648.7A CN116346113B (en) | 2023-05-23 | 2023-05-23 | High-precision current-controlled load switch circuit and trimming method thereof |
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| CN202310584648.7A CN116346113B (en) | 2023-05-23 | 2023-05-23 | High-precision current-controlled load switch circuit and trimming method thereof |
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| CN116346113B true CN116346113B (en) | 2023-08-11 |
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| CN116346113A (en) | 2023-06-27 |
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