CN114793060A - Linear voltage regulator and power management chip - Google Patents
Linear voltage regulator and power management chip Download PDFInfo
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- CN114793060A CN114793060A CN202110095761.XA CN202110095761A CN114793060A CN 114793060 A CN114793060 A CN 114793060A CN 202110095761 A CN202110095761 A CN 202110095761A CN 114793060 A CN114793060 A CN 114793060A
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- 239000004065 semiconductor Substances 0.000 claims description 8
- 230000005669 field effect Effects 0.000 claims description 7
- 229910044991 metal oxide Inorganic materials 0.000 claims description 7
- 150000004706 metal oxides Chemical group 0.000 claims description 7
- 238000005070 sampling Methods 0.000 claims description 5
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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Abstract
The utility model relates to the field of power electronics, and provides a linear voltage stabilizer with short-circuit protection and a power management chip.A short-circuit current-limiting module is utilized to generate a short-circuit indication signal according to the detection of short-circuit judgment voltage on output voltage during the normal working period of the linear voltage stabilizer, the voltage drop of a power tube is controlled during the period that the short-circuit indication signal is in an invalid state so as to provide the current output voltage, and the output current is controlled to be preset short-circuit current in a clamping manner during the period that the short-circuit indication signal is in an effective state; and the starting protection module is utilized to control the short-circuit current-limiting module to generate a short-circuit indication signal in an invalid state during the starting period of the linear voltage stabilizer, and control the short-circuit current-limiting module to generate a short-circuit indication signal in an valid state during the period that the linear voltage stabilizer is started and enters a normal working state. Therefore, full-load starting of the linear voltage regulator can be realized, short-circuit power consumption can be effectively reduced after the linear voltage regulator is started, and the chip reliability is improved while the chip is protected.
Description
Technical Field
The disclosure relates to the field of power electronics, in particular to a linear voltage regulator with short-circuit protection and a power management chip.
Background
Linear regulators (such as low dropout regulators (LDO) have low cost, low noise, and low static current, and are therefore widely used in power management and other application systems. In a power management chip integrated with a linear regulator, the linear regulator supplies a relatively large current. A conventional low dropout linear regulator (LDO)100 is shown in fig. 1, and includes: the error amplifier EA, the power tube Mp1 and the resistance feedback network formed by the first resistance Rf1 and the second resistance Rf 2. The output voltage Vout drives a load current Iout and a load capacitor Cout. Steady-state output voltage:
Vout0＝Vref*(Rf1+Rf2)/Rf1 (1)
generally, the power tube Mp1 is large in size due to low voltage difference, and can provide a large Current capability, and for safety, the circuit needs to be added with a Current limiting module (Current Limit), so that the Current capability of the Mp1 is limited to a certain value (Ilimit). To ensure that the rated load current (Iout0) can be output, Ilimit needs to be larger than Iout 0.
When the output is short-circuited, the output end of the linear regulator is directly grounded, an excessive current flows through the power tube Mp1 of the linear regulator 100, the voltage difference borne by the chip is the power supply voltage Vdd, and the power loss on the power tube Mp1 is the product of the difference between the power supply voltage Vdd and the output voltage Vout of the linear regulator 100 and the limiting current: and Ilimit × Vdd, for example, 1A for Ilimit, 10V for Vdd, and 10W for output power. Such a large power may cause damage to the entire power management chip, and therefore, a Short Current Limit (Short Current Limit) module is usually required in the linear regulator 100 to prevent damage to the linear regulator 100 and the power management chip when the load is Short-circuited.
In the prior art, a common short-circuit protection method of a linear regulator is as follows: when the output voltage of the linear voltage stabilizer is detected to be lower than a certain value, the output current is limited to be smaller than a short-circuit limiting current with a lower value, so that the power tube is prevented from being burnt out due to overlarge current flowing through the power tube, and short-circuit protection of the linear voltage stabilizer is realized. Referring to fig. 2, an improved linear regulator 200 is disclosed on the basis of the linear regulator shown in fig. 1, in which a current limiting module 210 and a short-circuit current limiting module 220 are additionally provided between an error amplifier EA and a power tube Mp1, and in order to reduce power consumption, a short-circuit current (Ishort) is designed to be smaller than a rated current Iout0, for example, 0.05A, so that the power after short-circuit is only 0.05A × 10V — 0.5W, thereby achieving a protection effect.
When the short-circuit protection method shown in fig. 2 in the prior art is used to implement the short-circuit protection of the linear regulator, the starting process of the output voltage Vout is as follows:
since the load capacitor Cout has no charge initially, the output voltage starts from initial 0V, and is divided by the first resistor Rf1 and the second resistor Rf2, the positive input terminal of the error amplifier EA is also 0V, which is smaller than the reference voltage Vref at the negative input terminal, so the output of the error amplifier EA is low, that is, the gate of the power tube Mp1 is low, Mp1 is turned on to charge the load capacitor Cout, and the output voltage rises until it rises to the steady output voltage.
At startup, the short-circuit current-limiting module 220 may consider the initial 0V to be a short-circuit condition, and may limit the current of Mp1 to Ishort. If the load current is the rated current Iout0, since the current provided by isoport < Iout0 and Mp1 is completely absorbed by the load current, no extra current is charged for Cout, and therefore the output voltage cannot be started, that is, full-load start cannot be realized. If the short-circuit current-limiting module 220 is removed or the short-circuit current value is increased, the power consumption of the chip during short circuit is increased, too large short-circuit power consumption easily causes temperature rise in the power management chip, and the risk of short circuit burnout is increased, or when the temperature rises to a certain value, a thermal protection module in the power management chip may be triggered, so that all circuits of the whole power management chip are turned off, and normal work of the chip is affected.
Disclosure of Invention
In order to solve the technical problem, the present disclosure provides a linear regulator and a power management chip with short-circuit protection, which can implement full-load start of the linear regulator, and after the linear regulator is started, can effectively reduce short-circuit power consumption, avoid damage to the chip, and improve reliability of the chip while implementing chip protection.
In one aspect, the present disclosure provides a linear regulator with short-circuit protection, which has a power tube connected between a voltage input end and a voltage output end, and a voltage feedback loop, where the voltage feedback loop controls on/off of the power tube by sampling an output of the voltage output end to provide an output current, and a load capacitor provides an output voltage according to the output current, where the linear regulator further includes:
the current limiting module is used for clamping and controlling the magnitude of the output current during the normal working period of the linear voltage stabilizer;
a short-circuit current-limiting module, configured to generate a short-circuit indication signal according to detection of the short-circuit determination voltage on the output voltage during normal operation of the linear regulator, control a voltage drop of the power tube during an invalid state of the short-circuit indication signal to provide a current output voltage, and clamp and control the output current to a preset short-circuit current during an valid state of the short-circuit indication signal;
and the starting protection module is connected with the short-circuit current-limiting module and used for controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an invalid state during the starting period of the linear voltage regulator and controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an valid state during the period that the linear voltage regulator is started and enters normal work.
Preferably, the aforementioned start-up protection module comprises:
a first inverter, configured to detect the input voltage, and output a first control voltage at a high level in response to the input voltage being less than a preset inversion threshold voltage, or output a first control voltage at a low level in response to the input voltage being greater than the inversion threshold voltage;
a delay unit connected to an output terminal of the first inverter for generating a second control voltage according to the first control voltage,
and the delay time of the delay unit is longer than the starting time of the output voltage.
Preferably, the short circuit current limiting module includes:
and a non-inverting input end of the first comparator is connected to the short-circuit judgment voltage, an inverting input end of the first comparator is connected to the output voltage, and an output end of the first comparator provides a comparison signal.
Preferably, the linear regulator further comprises:
and the input end of the logic AND gate is respectively connected with the output end of the first comparator and the output end of the delay unit, and the output end of the logic AND gate is connected with the current limiting module and used for providing the short circuit indication signal.
Preferably, during the start-up period of the linear regulator, the second control voltage is maintained at a low level, and the short-circuit indication signal is maintained at a low level, where the low level is used to represent an invalid state of the short-circuit indication signal;
during normal operation of the linear regulator, the second control voltage maintains a high level state, and the short-circuit indication signal is in a high level state in response to the output voltage being less than the short-circuit determination voltage, wherein the high level state is used to represent an active state of the short-circuit indication signal.
Preferably, the aforementioned delay unit includes:
a first transistor, a control end of which is connected with the output end of the first inverter and is connected with the first control voltage, and a second end of which is grounded;
a first current source and a first capacitor connected in series between the voltage input terminal and ground, and a connection node between the first current source and the first capacitor is connected to the first terminal of the first transistor;
a second inverter, the input end of which is connected with the connection node between the first current source and the first capacitor;
and the input end of the third inverter is connected with the output end of the second inverter, and the output end of the third inverter is used for providing the second control voltage.
Preferably, the aforementioned current limiting module comprises:
a second transistor and a third transistor connected in series between the voltage input terminal and ground, wherein a control terminal of the second transistor is connected to a control terminal of the power transistor, and a first terminal of the third transistor is connected to a control terminal of the third transistor;
a second current source and a fourth transistor connected in series between the voltage input terminal and ground, a control terminal of the fourth transistor being connected to a control terminal of the third transistor;
a fifth transistor and a third current source connected in parallel to two ends of the second current source, wherein a control end of the fifth transistor is connected to an output end of the logic and gate for accessing the short circuit indication signal;
and a sixth transistor, wherein a first end of the sixth transistor is connected to the voltage input terminal, a second end of the sixth transistor is connected to the control end of the power transistor, and the control end of the sixth transistor is connected to a connection node between the second current source and the fourth transistor.
Preferably, the width-to-length ratio of the power transistor to the second transistor is M: 1, and the width-to-length ratio of the third transistor to the fourth transistor is N: 1,
wherein, either one of M and N is a positive real number larger than 0.
Preferably, the aforementioned voltage feedback loop comprises:
a first resistor and a second resistor connected in series between the voltage output terminal and ground, and a connection node of the first resistor and the second resistor is used for providing a feedback voltage;
the negative input end of the error amplifier is connected with a preset reference voltage, the positive input end of the error amplifier is connected with the feedback voltage, the output end of the error amplifier is connected with the control end of the power tube and used for providing a switch control signal, and the switch control signal is used for controlling the on-off of the power tube so as to adjust the output voltage provided by the load capacitor.
Preferably, any one of the power transistor, the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor is a metal oxide semiconductor field effect transistor.
Preferably, the first transistor, the third transistor and the fourth transistor are all N-type metal oxide semiconductor field effect transistors, and the power transistor, the second transistor, the fifth transistor and the sixth transistor are all P-type metal oxide semiconductor field effect transistors.
This disclosure of another aspect also provides a power management chip, which includes: the linear regulator as described above.
The beneficial effect of this disclosure is: the present disclosure provides a linear voltage regulator with short-circuit protection and a power management chip, the linear voltage regulator has a power tube connected between a voltage input end and a voltage output end, and a voltage feedback loop, the voltage feedback loop controls the on/off of the power tube by sampling the output of the voltage output end to provide an output current, a load capacitor provides an output voltage according to the output current, wherein, the linear voltage regulator further comprises: the current limiting module is used for clamping and controlling the magnitude of the output current during the normal operation of the linear voltage regulator; the short-circuit current limiting module is used for generating a short-circuit indication signal according to the detection of the short-circuit judgment voltage on the output voltage during the normal working period of the linear voltage regulator, controlling the voltage drop of the power tube during the period when the short-circuit indication signal is in an invalid state so as to provide the current output voltage, and clamping and controlling the output current to be a preset short-circuit current during the period when the short-circuit indication signal is in an valid state; and the starting protection module is used for controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an invalid state during the starting period of the linear voltage regulator and controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an valid state during the period that the linear voltage regulator is started and enters normal operation. The full-load starting of the linear voltage stabilizer can be realized, after the linear voltage stabilizer is started, whether the linear voltage stabilizer is in a short-circuit state or not is judged quickly through detection of output voltage, and in response to detected short circuit, the output current is clamped and controlled to preset short-circuit current, so that the short-circuit power consumption can be effectively reduced, the function damage of a chip is avoided, and the reliability of the chip is improved while the chip is protected.
Drawings
The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of the embodiments of the present disclosure with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a linear regulator disclosed in the prior art;
fig. 2 shows a schematic diagram of a linear regulator according to the prior art disclosure, which is improved based on the scheme shown in fig. 1;
fig. 3 is a schematic diagram illustrating a structure of a linear regulator according to an embodiment of the disclosure;
FIG. 4 is a schematic diagram of a start-up protection module of the linear regulator shown in FIG. 3;
FIG. 5 is a circuit diagram of the blocks of the linear regulator shown in FIG. 3;
fig. 6 is a timing diagram illustrating operation of some signals in the linear regulator shown in fig. 3.
Detailed Description
To facilitate an understanding of the present disclosure, the present disclosure will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present disclosure are set forth in the accompanying drawings. This disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It should be understood that in the following description, "circuitry" may comprise singly or in combination hardware circuitry, programmable circuitry, state machine circuitry, and/or elements capable of storing instructions executed by programmable circuitry. When an element or circuit is referred to as being "connected to" another element or element/circuit is referred to as being "connected between" two nodes, it may be directly coupled or connected to the other element or intervening elements may be present, and the connection between the elements may be physical, logical, or a combination thereof. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, it is intended that there are no intervening elements present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the disclosure herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.
The present disclosure is described in detail below with reference to the accompanying drawings.
Fig. 3 is a schematic diagram illustrating a structure of a linear regulator according to an embodiment of the present disclosure, fig. 4 is a schematic diagram illustrating a structure of a start-up protection module in the linear regulator illustrated in fig. 3, and fig. 5 is a schematic diagram illustrating a circuit structure of each module in the linear regulator illustrated in fig. 3.
Referring to fig. 3 to fig. 5, in one aspect, the present disclosure provides a linear regulator 300 with short-circuit protection, which has a power tube Mp1 connected between a voltage input terminal and a voltage output terminal, and a voltage feedback loop, where the voltage feedback loop controls on/off of the power tube Mp1 by sampling an output of the voltage output terminal to provide an output current Iout, and a load capacitor Cout provides an output voltage Vout according to the output current Iout, where the linear regulator 300 further includes at least: a current limit module 310, a short circuit current limit module 320 and a start-up protection module 330,
the current limiting module 310 is configured to clamp the output current Iout during the normal operation of the linear regulator 300; the short-circuit current-limiting module 320 is configured to generate a short-circuit indication signal V4 according to the detection of the short-circuit determination voltage Vref1 on the output voltage Vout during the normal operation of the linear regulator 300, control the voltage drop of the power transistor Mp1 to provide the current output voltage Vout when the short-circuit indication signal V4 is in the inactive state, and clamp and control the output current Iout to a preset short-circuit current Ishort when the short-circuit indication signal V4 is in the active state; the start-up protection module 330 is connected to the short-circuit current limiting module 320, and is configured to control the short-circuit current limiting module 320 to generate the inactive short-circuit indication signal V4 during the start-up period of the linear regulator 300, and control the short-circuit current limiting module 320 to generate the active short-circuit indication signal V4 during the start-up period of the linear regulator 300.
Further, referring to fig. 4, the aforementioned start protection module 330 includes: a first inverter 331 and a delay unit 332,
the first inverter 331 is configured to detect a power supply voltage Vdd connected to the voltage input terminal, and in response to the power supply voltage Vdd being less than a preset inversion threshold voltage (not shown), the first inverter 331 outputs a first control voltage V1 at a high level, or in response to the power supply voltage Vdd being greater than the preset inversion threshold voltage, the first inverter 331 outputs a first control voltage V1 at a low level;
the delay unit 332 is connected to the output end of the first inverter 331 for generating a second control voltage V2 according to the first control voltage V1, and the delay time t0 of the delay unit 332 is longer than the start time tr of the output voltage Vout, as shown in fig. 6.
Further, referring to fig. 5, the short-circuit current-limiting module 320 at least includes a first comparator 321, a non-inverting input terminal of the first comparator 321 is connected to the short-circuit determination voltage Vref1, an inverting input terminal of the first comparator 321 is connected to the output voltage Vout, and an output terminal of the first comparator provides the comparison signal V3.
Further, the linear regulator 300 further includes a logic and gate 301, wherein inputs of the logic and gate 301 are respectively connected to the output of the first comparator 321 and the output of the delay unit 332, and an output of the logic and gate 301 is connected to the current limiting module 310, so as to provide the short circuit indication signal V4.
Further, during the start-up of the linear regulator 300, the second control voltage V2 is maintained at a low level, and the short-circuit indication signal V4 is maintained at a low level, which is used to indicate the invalid state of the short-circuit indication signal V4;
during the normal operation of the linear regulator 300, the second control voltage V2 is maintained at a high level, and the short-circuit indication signal V4 is in a high level state in response to the output voltage Vout being less than the short-circuit determination voltage Vref1, the high level state indicating an active state of the short-circuit indication signal V4.
Further, the aforementioned delay unit 332 includes: a transistor Mn3, a current source I2, a capacitor C2, a second inverter 3321 and a third inverter 3322,
wherein, the control terminal of the transistor Mn3 is connected to the output terminal of the first inverter 331, the first control voltage V1 is connected, and the second terminal is grounded; the current source I2 and the capacitor C2 are connected in series between the voltage input terminal and the ground, and the connection node between the current source I2 and the capacitor C2 is connected to the first terminal of the transistor Mn 3; the input terminal of the second inverter 3321 is connected to the connection node between the current source I2 and the capacitor C2; the input terminal of the third inverter 3322 is connected to the output terminal of the second inverter 3321, and the output terminal thereof is used for providing the second control voltage V2.
In the delay unit 332, the capacitor C2 is charged by the current source I2, and the signal delay of the power supply voltage Vdd at the rising edge is realized by shaping the second inverter 3321 and the third inverter 3322, and the delay time is t 0.
Further, the aforementioned current limiting module 310 includes: a transistor Mp2, a transistor Mp3, a transistor Mp4, a transistor Mn1, a transistor Mn2, a current source I0, and a current source I1,
the transistor Mp2 and the transistor Mn1 are connected in series between the voltage input terminal and the ground, the control terminal of the transistor Mp2 is connected to the control terminal of the power tube Mp1, and the first terminal of the transistor Mn1 is connected to its own control terminal;
the current source I0 and the transistor Mn2 are connected in series between the voltage input terminal and ground, and the control terminal of the transistor Mn2 is connected to the control terminal of the transistor Mn 1;
the transistor Mp4 and the current source I1 are connected in parallel to both ends of the current source I0, and the control end of the transistor Mp4 is connected to the output end of the logic and gate 301 for receiving the short circuit indication signal V4;
the transistor Mp3 has a first terminal connected to the voltage input terminal, a second terminal connected to the control terminal of the power transistor Mp1, and a control terminal connected to the connection node between the current source I0 and the transistor Mn 2.
Further, the width-to-length ratio of the power transistor Mp1 to the transistor Mp2 is M: 1, and the width-to-length ratio of the transistor Mn1 to the transistor Mn2 is N: 1, wherein any one of M and N is a positive real number greater than 0.
Further, the aforementioned voltage feedback loop comprises: a first resistor Rf1, a second resistor Rf2, and an error amplifier EA,
the first resistor Rf1 and the second resistor Rf2 are connected in series between the voltage output terminal and the ground, and the connection node of the first resistor Rf1 and the second resistor Rf2 is used for providing the feedback voltage Vfb;
the negative input terminal of the error amplifier EA is connected to a preset reference voltage Vref, the positive input terminal is connected to the feedback voltage Vfb, and the output terminal is connected to the control terminal of the power tube Mp1 for providing a switching control signal for controlling the on/off of the power tube Mp1 to adjust the output voltage Vout provided by the load capacitor Cout.
Further, any one of the power Transistor Mp1, the Transistor Mn3, the Transistor Mp2, the Transistor Mn1, the Transistor Mn2, the Transistor Mp4, and the Transistor Mp3 is a Metal Oxide Semiconductor field Effect Transistor (MOS Transistor).
Furthermore, the transistors Mn3, Mn1, and Mn2 are all N-type MOS transistors, and the power transistor Mp1, the transistor Mp2, the transistor Mp4, and the transistor Mp3 are all P-type MOS transistors. The structure and operation of the linear regulator 300 will be described based on this, but the embodiment of the present invention is not limited thereto. Those skilled in the art can set the aforementioned power transistor Mp1, transistor Mn3, transistor Mp2, transistor Mn1, transistor Mn2, transistor Mp4 and transistor Mp3 as different types of transistors according to actual needs, and adaptively adjust the related circuits to implement alternative embodiments of the present invention.
Referring to fig. 2, the power tube Mp1 is generally large in size due to low voltage difference, and can provide a large Current capability, for safety, the circuit needs to add a Current limiting module (Current Limit)210 to Limit the Current capability of the power tube Mp1 to a certain value (assuming that the limiting Current is Ilimit), and in order to ensure that the rated load Current (Iout0) can be output, the limiting Current Ilimit needs to be larger than the value set by the rated load Current Iout 0.
When the output voltage Vout malfunctions and is shorted to ground, the voltage difference borne by the chip is the power supply voltage Vdd, and the power of the chip is Ilimit Vdd, for example, when the limiting current Ilimit is 1A, and the power supply voltage Vdd is 10V, the power is 10W. At such high power, the chip is easily burned out, so that a Short Current Limit (Short Current Limit)220 needs to be added. In order to reduce power consumption, the short-circuit current (Ishort) is designed to be smaller than the rated load current Iout0, for example, 0.05A, so that the power after short-circuit is only 0.05A × 10V — 0.5W, thereby playing a role of protection.
However, when the output voltage Vout of the linear regulator 200 (or chip) is started, since the load capacitor Cout has no charge initially, the output voltage Vout starts from initial 0V, a feedback voltage is provided through the voltage dividing node of the first resistor Rf1 and the second resistor Rf2, the positive input terminal of the error amplifier EA is also 0V, which is smaller than the reference voltage Vref connected to the negative input terminal, so that the output of the error amplifier EA is low, that is, the gate of the power tube Mp1 is low, Mp1 is turned on to charge the load capacitor Cout, and the output voltage Vout rises until it rises to the steady-state output voltage Vout.
During startup, the short-circuit current limiting module 220 may consider the initial 0V as a short-circuit state, and may limit the current of the power tube Mp1 to the short-circuit current Ishort. If the output current is the rated load current Iout0, since Ishort < Iout0, the current provided by the power transistor Mp1 is completely absorbed by the load current, and no excess current charges the load capacitor Cout, so the output voltage Vout cannot achieve full load start.
In the linear regulator 300 with short-circuit protection provided by the embodiment of the present disclosure, the start-up protection module 330 is added to control the short-circuit current-limiting module 320, and the start-up protection module is matched with the logic control of the logic and gate 301, so as to control the short-circuit current-limiting module 320 to generate the short-circuit indication signal V4 in the invalid state during the start-up of the linear regulator 300, and control the short-circuit current-limiting module 320 to generate the short-circuit indication signal V4 in the valid state during the normal operation of the linear regulator 300 after the start-up is completed, thereby realizing the full-load start-up of the linear regulator, and after the output voltage Vout of the linear regulator is started up, the linear regulator 300 is rapidly determined whether the linear regulator 300 is in the short-circuit state by detecting the output voltage Vout, and in response to the detected short-circuit, the output current Iout is clamp-controlled to the preset short-circuit current Ishort, thereby effectively reducing the short-circuit power consumption and avoiding the chip damage, the chip reliability is improved while the chip is protected.
In a specific embodiment, the power transistor Mp1 and the transistor Mp2 of the linear regulator 300 form a current mirror, the transistor Mp2 mirrors the current flowing through the power transistor Mp1, then mirrors the current of the transistor Mn2 through the transistor Mn1, compares the current with the current provided by the reference current source I0, and feeds back the current to the gate of the power transistor Mp1 through controlling the gate of the transistor Mp3, the negative terminal of the first comparator 321 in the short-circuit current-limiting module 320 is connected to the output voltage Vout, the positive terminal is connected to the short-circuit determination voltage Vref1, and the output comparison signal V3 provides the short-circuit indication signal V4 in an active or inactive state to the gate of the transistor Mp4 through logic control with the second control voltage V2.
Further, the second control voltage V2 is logically anded with the comparison signal V3 output by the first comparator 321 in the short-circuit current-limiting module 320: after the power supply voltage Vdd rises, the second control voltage V2 rises in a delayed manner, and when the second control voltage V2 is at a low level, the output of the logic and gate 301 is at a low level, that is, the transistor Mp4 is turned on, and when power is turned on, the output current Iout is limited to be a limiting current: ilimit (I0+ I1) × M × N, so that the output current Iout remains substantially constant during the start-up, the output voltage Vout can rise smoothly, and an excessively high overshoot voltage is avoided.
When the second control voltage V2 turns to high level, the short-circuit indication signal V4 output by the logic and gate 301 is controlled by the short-circuit current-limiting module 320, and the original short-circuit protection is still maintained.
Specifically, referring to fig. 6, during the startup period of the linear regulator 300, the power voltage Vdd is initially in the low level state before time t1, and then turns to the high level state at time t1, the first control voltage V1 output by the first inverter 331 in the startup protection module 330 is inverted from the low level to the high level at time t1, and the first control voltage V1 is delayed for a certain time t0 by the reverse Delay (Delay) unit 332 to obtain the second control voltage V2 in the high level.
During the delay time t0 (start-up), when the second control voltage V2 is at a low level, the logic and gate 301 controls the short-circuit current-limiting module 320 to be inactive (the second control voltage V2 maintains a low level state, and the short-circuit indication signal V4 maintains a low level state, which is used to represent the inactive state of the short-circuit indication signal V4), so as to limit the output current of the power transistor Mp1 to (I0+ I1) × M × N, where M is the width-to-length ratio of the power transistor Mp1 to the transistor Mp 2; n is the width-to-length ratio of transistor Mn1 to transistor Mn2, and M and N are positive real numbers greater than 0.
I.e., the maximum current is controlled by the current limit module 310. During this time, even if the output tape is full at time t2, the output voltage Vout starts normally because the load current is smaller than the limit current Ilimit. Therefore, the delay time t0 is longer than the start time tr of the output voltage Vout, so that the full-load start effect is achieved.
After the delay time t0 reaches the time t3, the linear regulator 300 is started to enter a normal operation period, the second control voltage V2 is maintained at a high level state, and the logic of the logic and gate 301 is used to open the short-circuit current-limiting module 320 (the second control voltage V2 is maintained at a high level state, the short-circuit indication signal V4 is in a high level state in response to the output voltage Vout being less than the short-circuit determination voltage Vref1, and the high level state is used to represent the valid state of the short-circuit indication signal V4), so that the short-circuit current-limiting module 320 can generate the short-circuit indication signal V4 according to the detection of the short-circuit determination voltage Vout by the short-circuit determination voltage Vref1, when the output voltage Vout is greater than the short-circuit determination voltage Vref1, the output comparison signal V3 is at a low level, and gate 301 controls the generated short-circuit indication signal V4 to be in an invalid low level state, the transistor Mp4 is turned on, and the current source I1 is connected in parallel with the current source I0, and the limiting current is:
Ilimit＝(I0+I1)*M*N (1)
when the output voltage Vout is smaller than the short-circuit determination voltage Vref1, that is, it is determined that the output voltage Vout is short-circuited, and a high-level comparison signal is output, the logic and gate 301 at this time controls the generated short-circuit indication signal V4 to be in an active high-level state, the transistor Mp4 is turned off, and the short-circuit current at this time is:
Ishort＝I0*M*N (2)
therefore, the function of limiting the load current to be the short-circuit current Ishort which is smaller than the limiting current Ilimit is achieved, so that the linear voltage regulator 300 can realize self protection during short circuit and does not affect the normal operation of other circuits in an integrated circuit chip.
This disclosure of another aspect also provides a power management chip, which includes: the linear regulator 300 as described in the previously illustrated embodiment.
In summary, the embodiment of the present disclosure provides a linear regulator 300 with short-circuit protection and a power management chip integrated with the linear regulator 300, the linear regulator 300 has a power tube Mp1 connected between a voltage input end and a voltage output end, and a voltage feedback loop, the voltage feedback loop controls on/off of the power tube Mp1 by sampling an output of the voltage output end to provide an output current Iout, and a load capacitor Cout provides an output voltage Vout according to the output current Iout, wherein the linear regulator 300 further includes: a current limiting module 310, wherein the current limiting module 310 is configured to clamp the output current Iout during a normal operation of the linear regulator 300; a short-circuit current-limiting module 320, configured to generate a short-circuit indication signal V4 according to the detection of the output voltage Vout by the short-circuit determination voltage Vref1 during a normal operation of the linear regulator 300, control the voltage drop of the power transistor Mp1 during an inactive state of the short-circuit indication signal V4 to provide a current output voltage Vout, and clamp and control the output current Iout to a preset short-circuit current Ishort during an active state of the short-circuit indication signal V4; a start protection module 330, configured to control the aforementioned short circuit current limiting module 320 to generate the inactive short circuit indication signal V4 during the start of the linear regulator 300, and control the short circuit current limiting module 320 to generate the active short circuit indication signal V4 during the start of the linear regulator 300. Therefore, full-load starting of the linear voltage regulator 300 can be realized, after the output voltage Vout of the linear voltage regulator is started, whether the linear voltage regulator 300 is in a short-circuit state or not is quickly judged through detection of the output voltage Vout, and in response to the detected short circuit, the output current Iout is clamped and controlled to be a preset short-circuit current Ishort, so that short-circuit power consumption can be effectively reduced, the function of a chip is prevented from being damaged, and the reliability of the chip is improved while the chip is protected.
It should be noted that although the device is described herein as being some N-channel or P-channel device, or some N-type or P-type doped region, one of ordinary skill in the art will appreciate that complementary devices may also be implemented in accordance with the present invention. It will be understood by those skilled in the art that conductivity type refers to the mechanism by which conduction occurs, for example by conduction through holes or electrons, and thus does not relate to the doping concentration but to the doping type, for example P-type or N-type. It will be understood by those of ordinary skill in the art that the words "during", "when" and "when … …" as used herein in relation to the operation of a circuit are not strict terms referring to actions occurring immediately upon initiation of a startup action, but rather there may be some small but reasonable delay or delays, such as various transmission delays, between them and the reaction action (action) initiated by the startup action. The words "about" or "substantially" are used herein to mean that the value of an element (element) has a parameter that is expected to be close to the stated value or position. However, as is well known in the art, there is always a slight deviation that makes it difficult for the value or position to be exactly the stated value. It has been well established in the art that a deviation of at least ten percent (10%) for a semiconductor doping concentration of at least twenty percent (20%) is a reasonable deviation from the exact ideal target described. When used in conjunction with a signal state, the actual voltage value or logic state (e.g., "1" or "0") of the signal depends on whether positive or negative logic is used.
Moreover, it should be further noted that the relational terms such as first and second, and the like, herein are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Finally, it should be noted that: it should be understood that the above examples are only for clarity of illustration of the present disclosure, and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious changes and modifications can be made without departing from the scope of the present disclosure.
Claims (12)
1. A linear regulator with short circuit protection having a power tube connected between a voltage input and a voltage output, and a voltage feedback loop controlling turn-on and turn-off of the power tube by sampling an output of the voltage output to provide an output current, a load capacitor providing an output voltage according to the output current, wherein the linear regulator further comprises:
a current limiting module for clamping the magnitude of the output current during normal operation of the linear regulator;
the short-circuit current limiting module is used for generating a short-circuit indication signal according to the detection of the short-circuit judgment voltage on the output voltage during the normal working period of the linear voltage regulator, controlling the voltage drop of the power tube during the period when the short-circuit indication signal is in an invalid state so as to provide the current output voltage, and controlling the output current to be a preset short-circuit current in a clamping manner during the period when the short-circuit indication signal is in an valid state;
and the starting protection module is connected with the short-circuit current-limiting module and used for controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an invalid state during the starting period of the linear voltage stabilizer and controlling the short-circuit current-limiting module to generate a short-circuit indication signal in an valid state during the period when the linear voltage stabilizer is started and enters normal work.
2. The linear regulator of claim 1, wherein the start-up protection module comprises:
the first inverter is used for detecting the input voltage, responding to the fact that the input voltage is smaller than a preset overturning threshold voltage, and outputting a high-level first control voltage, or responding to the fact that the input voltage is larger than the overturning threshold voltage, and outputting a low-level first control voltage;
a delay unit connected to an output terminal of the first inverter for generating a second control voltage according to the first control voltage,
and the delay time of the delay unit is longer than the starting time of the output voltage.
3. The linear regulator of claim 2, wherein the short circuit current limiting module comprises:
and the non-inverting input end of the first comparator is connected with the short circuit judgment voltage, the inverting input end of the first comparator is connected with the output voltage, and the output end of the first comparator provides a comparison signal.
4. The linear regulator of claim 3, further comprising:
and the input end of the logic AND gate is respectively connected with the output end of the first comparator and the output end of the delay unit, and the output end of the logic AND gate is connected with the current limiting module and used for providing the short circuit indication signal.
5. The linear regulator according to claim 4, wherein during start-up of the linear regulator, the second control voltage remains low and the short indication signal remains low, the low indicating an inactive state of the short indication signal;
and during the normal working period of the linear voltage stabilizer, the second control voltage maintains a high level state, and the short circuit indication signal is in a high level state in response to the output voltage being smaller than the short circuit judgment voltage, wherein the high level state is used for representing the effective state of the short circuit indication signal.
6. The linear regulator of claim 4, wherein the delay unit comprises:
the control end of the first transistor is connected with the output end of the first inverter and is connected with the first control voltage, and the second end of the first transistor is grounded;
a first current source and a first capacitor connected in series between the voltage input terminal and ground, and a connection node between the first current source and the first capacitor is connected to a first terminal of the first transistor;
the input end of the second inverter is connected with a connecting node between the first current source and the first capacitor;
and the input end of the third inverter is connected with the output end of the second inverter, and the output end of the third inverter is used for providing the second control voltage.
7. The linear regulator of claim 6, wherein the current limiting module comprises:
the second transistor and the third transistor are connected between the voltage input end and the ground in series, the control end of the second transistor is connected with the control end of the power tube, and the first end of the third transistor is connected with the control end of the third transistor;
a second current source and a fourth transistor connected in series between the voltage input terminal and ground, a control terminal of the fourth transistor being connected with a control terminal of the third transistor;
a fifth transistor and a third current source which are connected in parallel with two ends of the second current source, wherein a control end of the fifth transistor is connected with an output end of the logic AND gate and used for accessing the short circuit indication signal;
and the first end of the sixth transistor is connected with the voltage input end, the second end of the sixth transistor is connected with the control end of the power tube, and the control end of the sixth transistor is connected with the connection node of the second current source and the fourth transistor.
8. The linear regulator of claim 7, wherein the width to length ratio of the power transistor to the second transistor is M: 1, and the width-to-length ratio of the third transistor to the fourth transistor is N: 1,
wherein, either one of M and N is a positive real number larger than 0.
9. The linear regulator of claim 1, wherein the voltage feedback loop comprises:
the voltage regulator comprises a first resistor and a second resistor which are connected between the voltage output end and the ground in series, and a connection node of the first resistor and the second resistor is used for providing a feedback voltage;
the negative input end of the error amplifier is connected with a preset reference voltage, the positive input end of the error amplifier is connected with the feedback voltage, the output end of the error amplifier is connected with the control end of the power tube and used for providing a switch control signal, and the switch control signal is used for controlling the on-off of the power tube so as to adjust the output voltage provided by the load capacitor.
10. The linear regulator according to claim 8, wherein any one of the power transistor, the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor is a metal oxide semiconductor field effect transistor.
11. The linear voltage regulator of claim 8, wherein the first, third and fourth transistors are all N-type metal oxide semiconductor field effect transistors, and the power transistor, second, fifth and sixth transistors are all P-type metal oxide semiconductor field effect transistors.
12. A power management chip, comprising:
the linear regulator of any one of claims 1-11.
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| CN117691863A (en) * | 2024-02-01 | 2024-03-12 | 荣耀终端有限公司 | Power management system and electronic equipment |
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