CN112859985A - Current limiting circuit of high-voltage large-current linear voltage stabilizer and implementation method - Google Patents
Current limiting circuit of high-voltage large-current linear voltage stabilizer and implementation method Download PDFInfo
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- CN112859985A CN112859985A CN202110066653.XA CN202110066653A CN112859985A CN 112859985 A CN112859985 A CN 112859985A CN 202110066653 A CN202110066653 A CN 202110066653A CN 112859985 A CN112859985 A CN 112859985A
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- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
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Abstract
The invention discloses a current limiting circuit of a high-voltage large-current linear voltage stabilizer and an implementation method thereof, the circuit is connected with a variable resistor R1 and a variable voltage dividing resistor R2 through a drain electrode of a high-voltage output power tube M1, one end of the variable resistor R1 is used as an output voltage VOUT port, a load equivalent resistor RL generates an output current Iout, the output current Iout flows through a sampling resistor Rsense, voltage difference is generated at two ends of the sampling resistor Rsense and is transmitted to a current sensing amplifier I3, the current sensing amplifier I3 amplifies a sampling signal and outputs the voltage to a current limiting comparator I1, and the current limiting comparator I1 compares the output voltage of the current sensing amplifier I3 with a reference voltage Vref input by a current limiting comparator I1, so as to realize current limiting. The invention is scientific and reasonable, is safe and convenient to use, and can very accurately correspond to the actual load capacity through the sampling of the aluminum wiring resistor on the active area at the output end of the high-voltage power tube M1 so as to realize current limiting in time.
Description
Technical Field
The invention relates to the technical field of power management, in particular to a current limiting circuit of a high-voltage large-current linear voltage stabilizer and an implementation method.
Background
In recent years, with the development of the integrated circuit industry, various power management chips have been developed. The power management chip currently applied to portable electronic products mainly includes discrete devices such as a switching regulator, a charge pump regulator, a low dropout regulator and a PMU power management unit. The low dropout regulator has been well developed because it has the advantages of simple structure, good stability, small ripple, low cost, low noise, small volume, small quiescent current, and can be simply integrated in other chips.
The low dropout regulator generally has a current-limiting protection circuit part to prevent the chip from overheating. However, most of the current-limiting structures of the existing low dropout linear regulators are realized by detecting the current of a power tube, and the specific implementation method is that the current of a detection tube which is matched with the power tube and is in a certain proportion is detected, when the current of the detection tube exceeds a set value, the current is limited, and a current-limiting action signal is sent out; when the detection tube is large and the proportion of the power tube to the detection tube is small, the current limiting value is accurate, but the increase of power consumption can be caused, the current limiting value is particularly serious in a low-power-consumption low-dropout linear voltage regulator, and simultaneously, the matching degree of the power tube and the detection tube, the channel length modulation effect and the non-ideality of an analog circuit can cause the inaccuracy of the current limiting value of a current limiting structure. Therefore, a current limiting circuit and an implementation method of a high-voltage large-current linear voltage regulator are urgently needed.
Disclosure of Invention
The present invention provides a current limiting circuit of a high voltage and large current linear regulator and a method for implementing the same, so as to solve the problems in the background art.
In order to solve the technical problems, the invention provides the following technical scheme:
a current limiting circuit of a high-voltage large-current linear voltage regulator comprises a high-voltage output power tube M1, a sampling resistor Rsense, a current limiting comparator I1, a driving module I2, a current sensing amplifier I3, an error amplifier I4, a variable resistor R1, a variable voltage dividing resistor R2 and a load equivalent resistor RL;
the input voltage VIN is connected with the source of the high-voltage output power tube M1 to provide power for the current-limiting circuit, the other end of the high-voltage output power tube M1 is connected with the variable resistor R1 and the variable voltage-dividing resistor R2 through the sampling resistor Rsense, one end of the variable resistor R1 is used as an output voltage VOUT port, the output voltage VOUT generates an output current Iout on the load equivalent resistor RL, the output current Iout flows through the sampling resistor Rsense, a voltage difference is generated at two ends of the sampling resistor Rsense, the sampling resistor Rsense collects a sampling signal of the output current Iout and transmits the sampling signal of the output current Iout into the current sensing amplifier I3, the current sensing amplifier I3 amplifies the sampling signal and outputs a voltage to the current limiting comparator I1, the current limiting comparator I1 compares the output voltage of the current sensing amplifier I3 with a reference voltage Vref input at the other end of the current limiting comparator I1, and when the current limiting comparator I1 works normally, the output voltage is normal; when the output current Iout increases and reaches a set current limiting value, the output of the current limiting comparator I1 is inverted, and the driving module I2 of the high-voltage output power tube M1 adjusts the gate voltage of the high-voltage power tube M1 to realize the current limiting function.
The invention uses the source of the high voltage power tube M1 to connect the input voltage VIN, the drain of the high voltage power tube M1 is connected to the variable resistor R1 through the sampling resistor Rsense, the variable resistor R1 is connected to the variable divider resistor R2, one end of the variable divider resistor R2 is used as the output voltage port, the current-limiting comparator I1 is connected to the driving module 2 of the high voltage output power tube M1, the gate voltage of the high voltage output power tube M1 can be adjusted, the variable resistor R1 and the variable divider resistor R2 are both connected to the input end of the error amplifier I4, the output end of the error amplifier I4 is connected to the driving module 2 of the high voltage output power tube M1, the output voltage VOUT of the set voltage value can be realized by adjusting the high voltage output power tube M1, the output voltage VOUT generates the output current Iout on the load equivalent resistor RL, the sampling resistor Rsense samples the output current Iout, the voltage difference is generated at the two ends of the sampling resistor Rsense, the voltage Vresense amplifier I3 amplifies the voltage, when the output current Iout exceeds the set current limiting value, the output signal of the current limiting comparator I1 is inverted, and the gate voltage of the high-voltage power tube M1 is controlled by the driving module I2 of the high-voltage power tube M1 to complete current limiting.
Further, the source of the high-voltage output power transistor M1 is connected to the input voltage VIN, the gate of the high-voltage output power transistor M1 is connected to the first interface of the driving module I2, the drain of the high-voltage output power transistor M1 and the first interface of the current sense amplifier I3 are both connected to the first end of the sampling resistor Rsense, the second interface of the current sense amplifier I3, the second end of the variable resistor R1 and the second end of the load equivalent resistor RL are both connected to the second end of the sampling resistor Rsense, the first end of the variable resistor R1 is connected to the second end of the variable voltage dividing resistor R2, the second end of the variable voltage dividing resistor R2 is connected to the first end of the error amplifier I4, the first end of the variable voltage dividing resistor R2 is grounded, the second end of the variable resistor R1 is used as an output voltage port, the first end of the load equivalent resistor RL is grounded, the second end of the error amplifier I4 is connected to the third interface of the driving module I2, the output pin of the current sense amplifier I3 is connected to the, the second interface of the current-limiting comparator I1 is connected with the reference voltage Vref, and the output interface of the current-limiting comparator I1 is connected with the second interface of the driving module I2.
The invention uses the source of the high voltage power tube M1 to connect the input voltage VIN, the drain of the high voltage power tube M1 is connected to the variable resistor R1 through the sampling resistor Rsense, the variable resistor R1 is connected to the variable divider resistor R2, one end of the variable divider resistor R2 is used as the output voltage port, the current-limiting comparator I1 is connected to the driving module 2 of the high voltage output power tube M1, the gate voltage of the high voltage output power tube M1 can be adjusted, the variable resistor R1 and the variable divider resistor R2 are both connected to the input end of the error amplifier I4, the output end of the error amplifier I4 is connected to the driving module 2 of the high voltage output power tube M1, the output voltage VOUT of the set voltage value can be realized by adjusting the high voltage output power tube M1, the output voltage VOUT generates the output current Iout on the load equivalent resistor RL, the sampling resistor Rsense samples the output current Iout, the voltage difference is generated at the two ends of the sampling resistor Rsense, the voltage Vresense amplifier I3 amplifies the voltage, when the output current Iout exceeds the set current limiting value, the output signal of the current limiting comparator I1 is inverted, and the gate voltage of the high-voltage power tube M1 is controlled by the driving module I2 of the high-voltage power tube M1 to complete current limiting.
Further, the sampling resistor Rsense is an aluminum wiring resistor above the active region, and the active region is located in the region where the high-voltage output tube M1 is located.
According to the invention, the sampling resistor Rsense is used for sampling the output current Iout, and the sampling resistor Rsense has better anti-interference capability and can accurately correspond to the actual load carrying capability.
Further, the current sense amplifier I3 is configured to amplify a sampling signal acquired by the sampling resistor Rsense, where the sampling signal is a sampling signal of the output current Iout.
The sampling resistor Rsense used by the invention has the characteristics of small volume, low cost, current impact resistance, high precision and high power, can accurately acquire an output current Iout signal, amplifies the sampling signal acquired by the sampling resistor Rsense by using the current sensing amplifier I3, and compares the amplified sampling signal with a reference voltage Vref input by a second interface of the current limiting comparator I1, thereby realizing the current limiting function.
Further, the current limiting circuit further comprises an error amplifier I4, and the error amplifier I4 is used for realizing the nominal voltage output of the output voltage VOUT.
The invention generates Vfb signals through the voltage division of the variable resistor R1 and the variable voltage dividing resistor R2, the Vfb signals are compared with the reference voltage Vref through the error amplifier I4 to gradually reach a stable set value, the error amplifier I4 is used for realizing the calibrated voltage output of the output voltage VOUT, and the error signals are amplified in the current limiting circuit so as to improve the sensitivity of the current limiting circuit, improve the adjusting precision and reduce the adjusting error.
A method for realizing a current limiting circuit of a high-voltage large-current linear voltage regulator comprises the following steps:
step S1: the input voltage VIN is an enable signal input by the high-voltage output power tube M1, the current-limiting circuit is reset, the current-limiting circuit is enabled, the current-limiting circuit starts to work normally, and the step S2 is executed;
step S2: inputting a reference voltage Vref to a first interface of the current-limiting comparator I1, increasing the reference voltage Vref to a voltage set value, synchronously increasing the output voltage VOUT of a second end of the variable resistor R1 to a calibrated voltage value, and turning to step S3;
step S3: the output current Iout generated by the load equivalent resistor RL rises until stable, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, the sampling resistor Rsense samples the output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between two ends of the sampling resistor Rsense, the voltage difference is transmitted to a first interface and a second interface of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense, the current sensing amplifier I3 amplifies a sampling signal of the output current Iout generated by the load equivalent resistor RL and outputs a voltage to a first interface of the current limiting comparator I1, and the step S4 is turned;
step S4: the current-limiting comparator I1 compares the output voltage of the current sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1, and when the current-limiting comparator I1 works normally, the output of the current-limiting comparator I1 is normal; when the output current Iout generated by the load equivalent resistor RL is increased and reaches the set current limiting value, the step S5 is executed;
step S5: the output of the current-limiting comparator I1 is inverted, an inverted signal is transmitted to a driving module I2 of the high-voltage power tube M1, and the driving module I2 adjusts the gate voltage of the high-voltage power tube M1 to realize the current-limiting function.
The source of a high-voltage output power tube M1 is connected with an input voltage VIN, the drain of the high-voltage output power tube M1 is connected with a variable resistor R1 and a variable voltage-dividing resistor R2 through a sampling resistor Rsense, the second end of the variable resistor R1 is used as an output voltage VOUT port, the sampling resistor Rsense collects a sampling signal of an output current Iout, a voltage difference is generated at two ends of the sampling resistor Rsense, the Vp end and the Vn end of the sampling resistor Rsense are connected with two input ends of a current sensing amplifier I3, the output end of the current sensing amplifier I3 is connected with a first interface of a current-limiting comparator I1, the output end of the current-limiting comparator I1 is connected with a second interface of a driving module I2, the driving module I2 is connected with the gate of the high-voltage output power tube M1, the driving module I2 can adjust the gate voltage of the high-voltage output power tube M1, the second interface of the error amplifier I4 is connected with a third interface of a driving module I2, and can adjust the output, meanwhile, the load equivalent resistor RL is used for generating an output current Iout, the output current Iout is generated on the load equivalent resistor RL through an output voltage VOUT, a sampling resistor Resense on an active area at one end of the high-voltage power tube M1 samples the output current Iout to obtain a sampling signal, the sampling signal is amplified and then compared with a reference voltage Vref input by a second interface of the current-limiting comparator I1, when the output current Iout exceeds a set current-limiting value, an output signal of the current-limiting comparator I1 is inverted, and the gate end voltage of the high-voltage power tube M1 is controlled through a driving module I2 of the high-voltage power tube M1, so that the purpose of current limiting is achieved, and the current-limiting circuit is suitable for being used as a current-limiting circuit in a high-current circuit.
Further, the high voltage power transistor M1 is a high voltage PMOS transistor or a high voltage NMOS transistor.
The high-voltage power tube M1 used in the invention has three pins which are generally a grid electrode, a source electrode and a drain electrode, the conduction and the cut-off between the drain electrode and the source electrode can be changed when a control signal is added between the grid electrode and the source electrode, the high-voltage output power tube M1 has the advantages of high input resistance, low noise, low power consumption, no secondary breakdown phenomenon, wide safe working area and the like, and the current limitation of the high-voltage heavy-current linear voltage stabilizer can be realized.
Further, the first interface and the second interface of the current-limiting comparator I1 are both input interfaces, the first interface and the second interface of the current-sensing amplifier I3 are both input interfaces, the first interface of the current-limiting comparator I1 is used for inputting the output voltage of the current-sensing amplifier I3, the second interface of the current-limiting comparator I1 is used for inputting the reference voltage Vref, and the first interface and the second interface of the current-sensing amplifier I3 are both used for inputting the voltage difference between the two ends of the sampling resistor Rsense.
According to the invention, a first interface and a second interface of a current sensing amplifier I3 are used for inputting sampling signals collected by a sampling resistor Rsense, a first interface of a current limiting comparator I1 is used for receiving amplified sampling signals output by the current sensing amplifier I3, a second interface of a current limiting comparator I1 is used for inputting reference voltage Vref, the current limiting comparator I1 compares data obtained by the two input interfaces, if the output current Iout exceeds a limited current limiting value, the output signal of the current limiting comparator I1 is inverted, and a driving module I2 of a high-voltage power tube M1 controls the gate end voltage of the high-voltage power tube M1, so that the current limiting function is realized.
Further, the implementation method of the current limiting circuit of the high-voltage large-current linear voltage regulator further comprises a reference voltage generating circuit, and the reference voltage generating circuit is used for providing a reference voltage Vref for the current limiting comparator I1.
According to the invention, the reference voltage Vref input by the second interface of the current-limiting comparator I1 needs to be provided by a reference voltage generating circuit, the reference voltage Vref provided by the reference voltage generating circuit can be compared with an amplified sampling signal, when the output current Iout exceeds a set current-limiting value, the output signal of the current-limiting comparator I1 is inverted, and then the gate voltage of the high-voltage power tube M1 is controlled through the driving module I2 of the high-voltage power tube M1, so that the current-limiting function is realized.
Further, in step S4, if the output current Iout generated by the load equivalent resistor RL is lower than the set current limit, the method repeats steps S3 to S5.
When the output current Iout is lower than the set current-limiting current, the output current Iout continues to rise, and current-limiting monitoring and control are carried out after the output current Iout rises to the set value, so that the high-voltage high-current linear voltage stabilizer can be used as a current-limiting circuit of the high-voltage high-current linear voltage stabilizer.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the source electrode of a high-voltage output power tube M1 is connected with an input voltage VIN, the drain electrode of a high-voltage output power tube M1 is connected with a variable resistor R1 and a variable voltage-dividing resistor R2 through a sampling resistor Rsense, and the second end of the variable resistor R1 is used as an output voltage VOUT port; the output end of the current-limiting comparator I1 is connected with the second interface of the driving module I2, the driving module I2 is connected with the grid electrode of the high-voltage output power tube M1, and the grid end voltage of the high-voltage output power tube M1 can be adjusted; the second interface of the error amplifier I4 is connected to the third interface of the driving module I2, and the high-voltage power tube M1 can be adjusted to realize the set output voltage value; the load equivalent resistor RL is used for generating an output current Iout; the drain electrode of the high-voltage power tube M1 is connected with a sampling resistor Resense, the sampling resistor Resense samples output current Iout to obtain a sampling signal, the sampling signal is amplified and then compared with reference voltage Vref input by a second interface of the input current-limiting comparator I1, when the output current Iout exceeds a set current-limiting value, the output signal of the current-limiting comparator I1 is inverted, and the gate voltage of the high-voltage power tube M1 is controlled through the driving module I2, so that the current-limiting purpose is achieved; the sampling resistor Rsense has better anti-interference capability and can accurately correspond to the actual load carrying capability; the problem that the current limiting value of a current limiting structure is inaccurate due to the matching degree of a power tube and a detection tube, the channel length modulation effect and the non-ideality of an analog circuit is solved, and the current limiting structure is suitable for being used as a current limiting circuit in a circuit with high and large current; the invention can accurately correspond to the actual load capacity by sampling the aluminum wiring resistor on the active area of the output end of the high-voltage power tube, improves the anti-interference capacity and can be applied to different occasions.
Drawings
FIG. 1 is a circuit schematic of a current limiting circuit of a high voltage high current linear regulator;
FIG. 2 is a schematic diagram of the structure of a high voltage power transistor M1 and a sampling resistor Rsense in a current limiting circuit of a high voltage and large current linear voltage regulator;
fig. 3 is a flow chart of a method for implementing a current limiting circuit of a high-voltage large-current linear regulator.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-3, the present invention provides the following technical solutions:
as shown in fig. 1, the current limiting circuit of a high voltage large current linear regulator includes a high voltage output power transistor M1, a sampling resistor Rsense, a current limiting comparator I1, a driving module I2, a current sensing amplifier I3, an error amplifier I4, a variable resistor R1, a variable divider resistor R2, and a load equivalent resistor RL;
the input voltage VIN is connected with the source of the high-voltage output power tube M1 to provide power for the current-limiting circuit, the other end of the high-voltage output power tube M1 is connected with the variable resistor R1 and the variable voltage-dividing resistor R2 through the sampling resistor Rsense, the second end of the variable resistor R1 is used as an output voltage VOUT port, the output voltage VOUT generates an output current Iout on the load equivalent resistor RL, the output current Iout flows through the sampling resistor Rsense, a voltage difference is generated at two ends of the sampling resistor Rsense, the sampling resistor Rsense collects a sampling signal of the output current Iout and transmits the sampling signal of the output current Iout into the current sensing amplifier I3, the current sensing amplifier I3 amplifies the sampling signal and outputs a voltage to the current limiting comparator I1, the current limiting comparator I1 compares the output voltage of the current sensing amplifier I3 with a reference voltage Vref input at the other end of the current limiting comparator I1, and when the current limiting comparator I1 works normally, the output of the current limiting comparator I1 is normal; when the output current Iout increases and reaches a set current limiting value, the output of the current limiting comparator I1 is inverted, and the driving module I2 of the high-voltage output power tube M1 adjusts the gate voltage of the high-voltage power tube M1 to realize the current limiting function.
The source of the high-voltage output power tube M1 is connected to the input voltage VIN, the gate of the high-voltage output power tube M1 is connected to the first interface of the driving module I2, the drain of the high-voltage output power tube M1 and the first interface of the current sense amplifier I3 are both connected to the first end of the sampling resistor Rsense, the second interface of the current sense amplifier I3, the second end of the variable resistor R1 and the second end of the load equivalent resistor RL are both connected to the second end of the sampling resistor Rsense, the first end of the variable resistor R1 is connected to the second end of the variable divider resistor R2, the second end of the variable divider resistor R2 is connected to the first end of the error amplifier I4, the first end of the variable divider resistor R2 is grounded, the second end of the variable resistor R1 is used as the output voltage VOUT port, the first end of the load equivalent resistor RL is grounded, the second end of the error amplifier I4 is connected to the third interface of the driving module I2, the output pin of the current-limiting comparator I1, the second interface of the current-limiting comparator I1 is connected with the reference voltage Vref, and the output interface of the current-limiting comparator I1 is connected with the second interface of the driving module I2.
The sampling resistor Rsense is an aluminum wiring resistor above the active area, and the active area is located in the area where the high-voltage output tube M1 is located.
The current sensing amplifier I3 is configured to amplify a sampling signal acquired by the sampling resistor Rsense, where the sampling signal is a sampling signal of the output current Iout.
The current limiting circuit further includes an error amplifier I4, and the error amplifier I4 is used for realizing the nominal voltage output of the output voltage VOUT.
As shown in fig. 2, a letter S indicates a source of the high voltage output power transistor M1, a letter G indicates a gate of the high voltage output power transistor M1, a letter D indicates a drain of the high voltage output power transistor M1, a first end and a second end of the sampling resistor Rsense are respectively connected to the drain of the high voltage output power transistor M1, a letter B indicates an input voltage VIN, the input voltage VIN is used for inputting an enable signal to the high voltage output power transistor M1 to enable the current limiting circuit, the sampling resistor Rsense further includes a Vp end and a Vn end, the sampling resistor Rsense collects a sampling signal of an output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between the Vp end and the Vn end of the sampling resistor Rsense, and a voltage difference is generated between the two ends of the sampling resistor Rsense, and the voltage difference is transmitted to the first interface and the second interface of the current sensing amplifier I3 through the Vp end and the Vn end of the sampling resistor Rsense.
As shown in fig. 3, a method for implementing a current limiting circuit of a high-voltage large-current linear regulator includes the following steps:
step S1, the input voltage VIN is an input enabling signal of the high-voltage output power tube M1, the current limiting circuit is reset, the current limiting circuit is enabled, the current limiting circuit starts to work normally, and the step S2 is carried out;
step S2: inputting a reference voltage Vref to a first interface of the current-limiting comparator I1, increasing the reference voltage Vref to a voltage set value, synchronously increasing the output voltage VOUT of a second end of the variable resistor R1 to a calibrated voltage value, and turning to step S3;
step S3: the output current Iout generated by the load equivalent resistor RL rises until stable, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, the sampling resistor Rsense samples the output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between two ends of the sampling resistor Rsense, the voltage difference is transmitted to a first interface and a second interface of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense, the current sensing amplifier I3 amplifies a sampling signal of the output current Iout generated by the load equivalent resistor RL and outputs a voltage to a first interface of the current limiting comparator I1, and the step S4 is turned;
step S4: the current-limiting comparator I1 compares the output voltage of the current sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1, and when the current-limiting comparator I1 works normally, the output of the current-limiting comparator I1 is normal; when the output current Iout generated by the load equivalent resistor RL is increased and reaches the set current limiting value, the step S5 is executed;
step S5: the output of the current-limiting comparator I1 is inverted, an inverted signal is transmitted to a driving module I2 of the high-voltage power tube M1, and the driving module I2 adjusts the gate voltage of the high-voltage power tube M1 to realize the current-limiting function.
The high-voltage power tube M1 is a high-voltage PMOS tube or a high-voltage NMOS tube.
The first interface and the second interface of the current-limiting comparator I1 are both input interfaces, the first interface and the second interface of the current-sensing amplifier I3 are both input interfaces, the first interface of the current-limiting comparator I1 is used for inputting the output voltage of the current-sensing amplifier I3, the second interface of the current-limiting comparator I1 is used for inputting the reference voltage Vref, and the first interface and the second interface of the current-sensing amplifier I3 are both used for inputting the voltage difference between two ends of the sampling resistor Rsense.
The implementation method of the current limiting circuit of the high-voltage large-current linear voltage regulator further comprises a reference voltage generating circuit, and the reference voltage generating circuit is used for providing a reference voltage Vref for the current limiting comparator I1.
In step S4, if the output current Iout generated by the load equivalent resistor RL is lower than the set current limit, the method repeats steps S3 to S5.
The working principle of the invention is as follows: the source electrode of the high-voltage output power tube M1 is connected with an input voltage VIN, the circuit is reset, the circuit is enabled, the current limiting circuit starts to work normally, the drain electrode of the high-voltage output power tube M1 is connected with a variable resistor R1 and a variable divider resistor R2 through a sampling resistor Rsense, the second end of a variable resistor R1 is used as an output voltage VOUT port, meanwhile, the output voltage VOUT generates an output current Iout on a load equivalent resistor RL, a sampling resistor Resense on one end of the high-voltage power tube M1 in an active area samples the output current Iout generated by the load equivalent resistor RL to obtain a sampling signal, a Vp end and a Vn end of the sampling resistor Rsense are connected with two input ends of a current sensing amplifier I3, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, a voltage difference is generated at the two ends of the sampling resistor Rsense, and is transmitted to the current sensing amplifier I3 through a first interface and a second interface of a current sensing, the current sensing amplifier I3 amplifies the sampling signal, the output end of the current sensing amplifier I3 is connected with the first interface of the current-limiting comparator I1, the output voltage of the current sensor I3 is transmitted to the first interface of the current-limiting comparator I1, the current-limiting comparator I1 compares the output voltage of the current sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1, and when the current sensing amplifier I1 works normally, the output of the current-limiting comparator I1 is normal; when the output current Iout generated by the load equivalent resistor RL increases and reaches a set current limiting value, the output of the output end of the current limiting comparator I1 is inverted, and the driving module I2 of the high-voltage output power tube M1 adjusts the gate voltage of the high-voltage output power tube M1, so that the current limitation of the high-voltage large-current linear voltage regulator is realized.
The first embodiment is as follows:
a current limiting circuit of a high-voltage large-current linear voltage regulator comprises a high-voltage output power tube M1, a sampling resistor Rsense, a current limiting comparator I1, a driving module I2, a current sensing amplifier I3, an error amplifier I4, a variable resistor R1, a variable voltage dividing resistor R2 and a load equivalent resistor RL;
the source of the high-voltage output power tube M1 is connected to the input voltage VIN, the gate of the high-voltage output power tube M1 is connected to the first interface of the driving module I2, the drain of the high-voltage output power tube M1 and the first interface of the current sense amplifier I3 are both connected to the first end of the sampling resistor Rsense, the second interface of the current sense amplifier I3, the second end of the variable resistor R1 and the second end of the load equivalent resistor RL are both connected to the second end of the sampling resistor Rsense, the first end of the variable resistor R1 is connected to the second end of the variable divider resistor R2, the second end of the variable divider resistor R2 is connected to the first end of the error amplifier I4, the first end of the variable divider resistor R2 is grounded, the second end of the variable resistor R1 is used as the output voltage VOUT port, the first end of the load equivalent resistor RL is grounded, the second end of the error amplifier I4 is connected to the third interface of the driving module I2, the output pin of the current-limiting comparator I1, a second interface of the current-limiting comparator I1 is connected with the reference voltage Vref, and an output interface of the current-limiting comparator I1 is connected with a second interface of the driving module I2;
the current limiting circuit of the high-voltage large-current linear voltage regulator further comprises a current sampling resistor Rsense, an output current Iout flows through the sampling resistor Rsense to generate a voltage difference, and the voltage difference is transmitted to the input end of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense to finish sampling of the output current Iout;
the output end of the current sensing amplifier I3 is connected to the input end of a current-limiting comparator I1, the other input end of the current-limiting comparator I1 is connected to a reference voltage Vref, the output end of the current-limiting comparator I1 is connected to a driving module I2 of a high-voltage power tube M1, and the driving module I2 of the high-voltage power tube M1 is used for adjusting the gate voltage of the high-voltage power tube M1;
a first end of the variable resistor R1 and a second end of the variable voltage-dividing resistor R2 are connected to an input end of an error amplifier I4, an output end of the error amplifier I4 is connected to a driving module I2 of the high-voltage power tube M1, and a driving module I2 of the high-voltage power tube M1 is used for adjusting the power tube M1 to realize a set output voltage value;
meanwhile, the load equivalent resistor RL is used for generating an output current Iout, an aluminum wire resistor Rsense on an active area of the high-voltage power tube M1 is used for sampling the output current Iout generated by the output voltage VOUT on the load equivalent resistor RL, a sampling signal is amplified and then compared with a reference voltage Vref, when the output current Iout generated by the load equivalent resistor RL exceeds a set current limiting value, an output signal of the current limiting comparator I1 is inverted, and then the gate end voltage of the high-voltage power tube M1 is controlled through a driving module I2 of the high-voltage power tube M1, so that the current limiting function is completed.
Example two:
a method for realizing a current limiting circuit of a high-voltage large-current linear voltage regulator comprises the following steps:
the input voltage VIN is an enable signal input by the high-voltage output power tube M1, the current limiting circuit is reset and enabled, and the current limiting circuit starts to work normally;
a reference voltage Vref is input into a first interface of the current-limiting comparator I1, the reference voltage Vref rises to a voltage set value, and the output voltage VOUT at the second end of the variable resistor R1 synchronously rises to a calibrated voltage value;
the output current Iout generated by the load equivalent resistor RL rises until the output current Iout is stable, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, the sampling resistor Rsense samples the output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between two ends of the sampling resistor Rsense, the voltage difference is transmitted to a first interface and a second interface of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense, and the current sensing amplifier I3 amplifies a sampling signal of the output current Iout generated by the load equivalent resistor RL and outputs voltage to a first interface of the current limiting comparator I1;
the current-limiting comparator I1 compares the output voltage of the current-sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1, and outputs a normal load when the normal working state is found.
Example three:
a method for realizing a current limiting circuit of a high-voltage large-current linear voltage regulator comprises the following steps:
the input voltage VIN is an enable signal input by the high-voltage output power tube M1, the current limiting circuit is reset and enabled, and the current limiting circuit starts to work normally;
a reference voltage Vref is input into a first interface of the current-limiting comparator I1, the reference voltage Vref rises to a voltage set value, and the output voltage VOUT at the second end of the variable resistor R1 synchronously rises to a calibrated voltage value;
the output current Iout generated by the load equivalent resistor RL rises until the output current Iout is stable, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, the sampling resistor Rsense samples the output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between two ends of the sampling resistor Rsense, the voltage difference is transmitted to a first interface and a second interface of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense, and the current sensing amplifier I3 amplifies a sampling signal of the output current Iout generated by the load equivalent resistor RL and outputs voltage to a first interface of the current limiting comparator I1;
the current-limiting comparator I1 compares the output voltage of the current sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1;
the output current Iout generated by the load equivalent resistor RL reaches a set current limiting value, the output of the current limiting comparator I1 is inverted, an inverted signal is transmitted to the driving module I2 of the high-voltage power tube M1, and the driving module I2 adjusts the gate end voltage of the high-voltage power tube M1 to realize the current limiting function.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (10)
1. The utility model provides a current-limiting circuit of high-pressure heavy current linear voltage regulator which characterized in that: the current limiting circuit comprises a high-voltage output power tube M1, a sampling resistor Rsense, a current limiting comparator I1, a driving module I2, a current sensing amplifier I3, an error amplifier I4, a variable resistor R1, a variable voltage dividing resistor R2 and a load equivalent resistor RL;
the input voltage VIN is connected with a source electrode of a high-voltage output power tube M1 to provide a power supply for a current limiting circuit, the other end of the high-voltage output power tube M1 is connected with a variable resistor R1 and a variable voltage-dividing resistor R2 through a sampling resistor Rsense, one end of the variable resistor R1 is used as an output voltage VOUT port, the output voltage VOUT generates an output current Iout on a load equivalent resistor RL, the output current Iout flows through a sampling resistor Rsense, a voltage difference is generated at two ends of the sampling resistor Rsense, the sampling resistor Rsense collects a sampling signal of the output current Iout and transmits the sampling signal of the output current Iout into a current sensing amplifier I3, the current sensing amplifier I3 amplifies the sampling signal and outputs a voltage to a current limiting comparator I1, the current limiting comparator I1 compares the output voltage of the current sensing amplifier I3 with a reference voltage Vref input at the other end of the current limiting comparator I1, when the current limiting comparator I1 works normally, the output of the current limiting comparator I1 is normal; when the output current Iout increases and reaches a set current limiting value, the output of the current limiting comparator I1 is inverted, and the driving module I2 of the high-voltage output power tube M1 adjusts the gate voltage of the high-voltage power tube M1 to realize the current limiting function.
2. The current-limiting circuit of a high-voltage large-current linear regulator according to claim 1, wherein: the source of the high-voltage output power tube M1 is connected to the input voltage VIN, the gate of the high-voltage output power tube M1 is connected to the first interface of the driving module I2, the drain of the high-voltage output power tube M1 and the first interface of the current sense amplifier I3 are both connected to the first end of the sampling resistor Rsense, the second interface of the current sense amplifier I3, the second end of the variable resistor R1 and the second end of the load equivalent resistor RL are both connected to the second end of the sampling resistor Rsense, the first end of the variable resistor R1 is connected to the second end of the variable voltage dividing resistor R2, the second end of the variable voltage dividing resistor R2 is connected to the first end of the error amplifier I4, the first end of the variable voltage dividing resistor R2 is grounded, the second end of the variable resistor R1 is used as the output voltage VOUT port, the first end of the load equivalent resistor RL is grounded, the second end of the error amplifier I4 is connected to the third interface of the driving module I2, an output pin of the current sensing amplifier I3 is connected with a first interface of a current-limiting comparator I1, a second interface of the current-limiting comparator I1 is connected with a reference voltage Vref, and an output interface of the current-limiting comparator I1 is connected with a second interface of a driving module I2.
3. The current-limiting circuit of a high-voltage large-current linear regulator according to claim 1, wherein: the sampling resistor Rsense is an aluminum wiring resistor above an active area, and the active area is located in the area where the high-voltage output tube M1 is located.
4. The current-limiting circuit of a high-voltage large-current linear regulator according to claim 1, wherein: the current sensing amplifier I3 is used for amplifying a sampling signal acquired by the sampling resistor Rsense, and the sampling signal is a sampling signal of the output current Iout.
5. The current-limiting circuit of a high-voltage large-current linear regulator according to claim 1, wherein: the current limiting circuit further comprises an error amplifier I4, wherein the error amplifier I4 is used for realizing the nominal voltage output of the output voltage VOUT.
6. A method for realizing a current limiting circuit of a high-voltage large-current linear voltage regulator is characterized by comprising the following steps: the method comprises the following steps:
step S1: the input voltage VIN is an enable signal input by the high-voltage output power tube M1, the current-limiting circuit is reset, the current-limiting circuit is enabled, the current-limiting circuit starts to work normally, and the step S2 is executed;
step S2: inputting a reference voltage Vref to a first interface of the current-limiting comparator I1, increasing the reference voltage Vref to a voltage set value, synchronously increasing the output voltage VOUT of a second end of the variable resistor R1 to a calibrated voltage value, and turning to step S3;
step S3: the output current Iout generated by the load equivalent resistor RL rises until stable, the output current Iout generated by the load equivalent resistor RL flows through the sampling resistor Rsense, the sampling resistor Rsense samples the output current Iout generated by the load equivalent resistor RL, a voltage difference is generated between two ends of the sampling resistor Rsense, the voltage difference is transmitted to a first interface and a second interface of the current sensing amplifier I3 through a Vp end and a Vn end of the sampling resistor Rsense, the current sensing amplifier I3 amplifies a sampling signal of the output current Iout generated by the load equivalent resistor RL and outputs a voltage to a first interface of the current limiting comparator I1, and the step S4 is turned;
step S4: the current-limiting comparator I1 compares the output voltage of the current sensing amplifier I3 received by the first interface of the current-limiting comparator I1 with the reference voltage Vref input by the second interface of the current-limiting comparator I1, and when the current-limiting comparator I1 works normally, the output of the current-limiting comparator I1 is normal; when the output current Iout generated by the load equivalent resistor RL is increased and reaches the set current limiting value, the step S5 is executed;
step S5: the output of the current-limiting comparator I1 is inverted, an inverted signal is transmitted to a driving module I2 of the high-voltage power tube M1, and the driving module I2 adjusts the gate voltage of the high-voltage power tube M1 to realize the current-limiting function.
7. The method according to claim 6, wherein the method comprises the following steps: the high-voltage power tube M1 is a high-voltage PMOS tube or a high-voltage NMOS tube.
8. The method according to claim 6, wherein the method comprises the following steps: the current-limiting comparator I1 is characterized in that a first interface and a second interface are input interfaces, the first interface and the second interface of the current-sensing amplifier I3 are input interfaces, the first interface of the current-limiting comparator I1 is used for inputting the output voltage of the current-sensing amplifier I3, the second interface of the current-limiting comparator I1 is used for inputting the reference voltage Vref, and the first interface and the second interface of the current-sensing amplifier I3 are both used for inputting the voltage difference between two ends of the sampling resistor Rsense.
9. The method according to claim 6, wherein the method comprises the following steps: the method also includes a reference voltage generation circuit for providing a reference voltage Vref for the current limited comparator I1.
10. The method according to claim 6, wherein the method comprises the following steps: in step S4, if the output current Iout generated by the load equivalent resistor RL is lower than the set current limit, step S3 to step S5 are repeated.
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