A low-power adaptive low-voltage high-voltage stabilizing circuit

Abstract

The application discloses a low-power adaptive low-voltage high-voltage stabilizing circuit, and relates to the field of integrated circuits. A negative input end of an operational amplifier is connected with a band gap reference voltage. A positive electrode of the operational amplifier is used for receiving a feedback voltage. The feedback voltage is used for representing an output voltage of a stabilizing circuit. An output end of the operational amplifier is connected with a first control end of a driving device. An output end of the driving device is connected with a control end of the stabilizing circuit. A second control end of the driving device is connected with the band gap reference voltage. The operational amplifier is used for transmitting a driving signal to the driving device under the condition that a first preset condition is met. The first preset condition is that the feedback voltage is greater than the band gap reference voltage. The driving device is used for controlling the stabilizing circuit based on the driving signal, so that the stabilizing circuit outputs a stable voltage. The application can adaptively output a stable voltage and has low cost.

Description

Technical Field

[0001] This invention relates to the field of integrated circuits, and in particular to a low-power adaptive low-voltage high-voltage regulator circuit. Background Technology

[0002] A voltage regulator circuit is a voltage conversion device that transforms the external power supply voltage of a chip into a stable voltage range usable by the chip's internal circuitry. It is a commonly used non-linear electronic voltage regulator circuit. The output power transistor in the circuit is controlled by an internal loop to output a stable voltage. The characteristic of this circuit is that it maintains a stable output voltage even under large variations in the power supply voltage, thus providing voltage to other circuits within the system.

[0003] Automotive-grade chips often need to adapt to both low and high power supply voltages in complex applications. As a result, the circuit structure is complex in practical applications. High-voltage MOS devices require a large amount of layout area due to the complexity of the process. Most devices operate at high voltage, which increases power consumption and thus increases cost. Summary of the Invention

[0004] The purpose of this invention is to provide a low-power adaptive low-voltage high-voltage regulator circuit that can adaptively output a stable voltage and is low in cost.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A low-power adaptive low-voltage high-voltage regulator circuit includes: an operational amplifier, a driver, and a voltage regulator circuit.

[0007] The negative input terminal of the operational amplifier is connected to the bandgap reference voltage; the positive terminal of the operational amplifier is used to receive the feedback voltage; the feedback voltage is used to characterize the output voltage of the voltage regulator circuit; the output terminal of the operational amplifier is connected to the first control terminal of the driving device; the output terminal of the driving device is connected to the control terminal of the voltage regulator circuit; the second control terminal of the driving device is connected to the bandgap reference voltage.

[0008] The operational amplifier is used to transmit a drive signal to the driving device under a first preset condition; the first preset condition is that the feedback voltage is greater than the bandgap reference voltage.

[0009] The driving device is used to control the voltage regulator circuit based on the driving signal, so that the voltage regulator circuit outputs a stable voltage.

[0010] Optionally, the driving device specifically includes:

[0011] Under the second preset condition, when a drive signal is received, the second drive transistor in the drive device is turned on, pulling down the voltage at the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable.

[0012] Under the second preset condition, when no drive signal is received, the charge pump in the drive device supplies power to the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable.

[0013] The second preset condition is

[0014] Among them, V OUT This is the output voltage of the voltage regulator circuit; The maximum VGS withstand voltage of the first driving transistor in the voltage regulator circuit; CP PRE The voltage supplied by the driving device to the driving terminal of the voltage regulator circuit; VTH is the voltage of the first driving transistor in the voltage regulator circuit.

[0015] Optionally, the voltage regulator circuit includes: a power supply, a first driving transistor, a first resistor, and a second resistor;

[0016] The gate of the first driving transistor is connected to the output terminal of the driving device; the drain of the first driving transistor is connected to the power supply; the source of the first driving transistor is connected to one end of the first resistor; the other end of the first resistor is connected to the second resistor; the other end of the second resistor is grounded; the other end of the first resistor is also connected to the positive terminal of the operational amplifier; the source of the first driving transistor serves as the output terminal of the voltage regulator circuit.

[0017] Optionally, the driving device includes: a charge pump, a second driving transistor, and a protection circuit;

[0018] The gate of the second driving transistor is connected to the output of the operational amplifier; the output of the charge pump is connected to the drain of the second driving transistor and the gate of the first driving transistor; the first input of the protection circuit is located between the charge pump and the gate of the first driving transistor; the second input of the protection circuit is connected to the bandgap reference voltage; the drain of the third driving transistor in the protection circuit is grounded.

[0019] The protection circuit is used to protect the first driving transistor.

[0020] Optionally, the protection circuit includes a first diode and a third driving transistor;

[0021] The cathode of the first diode is connected to the second output terminal of the charge pump; the anode of the first diode is connected to the source of the third driving transistor; the gate of the third driving transistor is connected to the bandgap reference voltage; and the drain of the third driving transistor is grounded.

[0022] Optionally, the output of the charge pump is connected to the drain of the second driving transistor and the gate of the first driving transistor respectively through a low-pass filter;

[0023] The low-pass filter is used to filter the output voltage of the charge pump.

[0024] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] This invention discloses a low-power adaptive low-voltage high-voltage regulator circuit. An operational amplifier transmits a drive signal to a driving device; the driving device controls the regulator circuit based on the drive signal, causing the regulator circuit to output a stable voltage. This invention provides an adaptive, stable output voltage at low cost. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The circuit diagram of the low-power adaptive low-voltage high-voltage regulator circuit provided by the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a low-power adaptive low-voltage high-voltage regulator circuit that can adaptively output a stable voltage in both high-voltage and low-voltage power supply ranges, and is low in cost.

[0030] This invention primarily aims to convert a wide-range power supply voltage from the chip's external environment into a stable low voltage within a narrow range to power the chip's internal low-voltage circuitry. For example, complex applications of automotive-grade chips often require adaptation to both low and high power supply voltages. Therefore, in practical applications, the circuit structure is complex, and high-voltage MOS devices, due to their complex manufacturing process, increase layout area. Furthermore, most devices operating at high voltages increase power consumption, thus raising costs. This invention introduces a simple, adaptive low-voltage high-voltage regulator circuit with only one high-voltage MOS device. When the power supply voltage is higher than the expected voltage, the output will stabilize at the specified output voltage; when the power supply voltage is lower than the expected voltage, the output voltage follows the power supply voltage, preventing excessively low output voltage due to large voltage drops within the regulator circuit, which could affect the normal operation of the chip's internal circuitry. This effectively reduces circuit complexity, power consumption, and area.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Due to the asymmetrical structure of high-voltage transistors in current BCD semiconductor processes, the gate-source voltage of high-voltage MOSFETs is not high, which is a voltage withstand issue that requires special attention in the design.

[0033] like Figure 1 As shown, the present invention provides a low-power adaptive low-voltage high-voltage regulator circuit, comprising: an operational amplifier, a driving device, and a voltage regulator circuit.

[0034] The negative input terminal VBG of the op-amp is connected to the bandgap reference voltage; the positive terminal VFB of the op-amp is used to receive the feedback voltage; the feedback voltage is used to characterize the output voltage of the voltage regulator circuit; the output terminal VO1 of the op-amp is connected to the first control terminal of the driver; the output terminal of the driver is connected to the control terminal of the voltage regulator circuit; the second control terminal of the driver is connected to the bandgap reference voltage.

[0035] The bandgap reference voltage is used to provide a reference voltage.

[0036] The operational amplifier is used to transmit a drive signal to the driving device under a first preset condition; the first preset condition is that the feedback voltage VFB is greater than the bandgap reference voltage VBG.

[0037] The switching gain of the op-amp is A, and the output of the op-amp is VO1 = (VFB - VBG) × A.

[0038] The driving device is used to control the voltage regulator circuit based on the driving signal, so that the voltage regulator circuit outputs a stable voltage.

[0039] Under the second preset condition, when a drive signal is received, the second drive transistor NM2 in the drive device is turned on, pulling down the voltage at the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable.

[0040] Under the second preset condition, when no drive signal is received, the charge pump in the drive device supplies power to the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable.

[0041] The second preset condition is

[0042] Among them, V OUT This is the output voltage of the voltage regulator circuit; The maximum VGS withstand voltage of the first driving transistor in the voltage regulator circuit; CP PRE The voltage supplied by the driving device to the driving terminal of the voltage regulator circuit; VTH is the voltage of the first driving transistor in the voltage regulator circuit.

[0043] The voltage regulator circuit includes: power supply VBAT, first driving transistor HVNM1, first resistor R1 and second resistor R2.

[0044] The gate of the first driving transistor HVNM1 is connected to the output terminal of the driving device; the drain of the first driving transistor HVNM1 is connected to the power supply VBAT; the source of the first driving transistor HVNM1 is connected to one end of the first resistor R1; the other end of the first resistor R1 is connected to the second resistor R2; the other end of the second resistor R2 is grounded; the other end of the first resistor R1 is also connected to the positive terminal VFB of the operational amplifier; the source of the first driving transistor HVNM1 serves as the output terminal of the voltage regulator circuit.

[0045] The first driving transistor HVNM1 is an NMOS high-voltage transistor. The Vds of the first driving transistor HVNM1 can withstand high voltage, and the high voltage withstand value of the first driving transistor HVNM1 can be adjusted according to the situation. The third driving transistor PM5 is a PMOS transistor with a Vds that can withstand a relatively high voltage. The gate voltage is connected to the VBG reference voltage. When the CP_OUT output voltage is too high, it can be pulled down to protect the low voltage withstand voltage Vds of the second driving transistor NM2 and the gate and source voltage VGS of the first driving transistor HVNM1.

[0046] The power supply VBAT is the external power supply voltage for the chip, which can be either high voltage or low voltage.

[0047] The driving device includes: a charge pump, a second driving transistor NM2, and a protection circuit.

[0048] The gate of the second driving transistor NM2 is connected to the output terminal VO1 of the operational amplifier; the output terminal of the charge pump is connected to the drain of the second driving transistor NM2 and the gate of the first driving transistor HVNM1; the first input terminal of the protection circuit is located between the charge pump and the gate of the first driving transistor HVNM1; the second input terminal of the protection circuit is connected to the bandgap reference voltage; the drain of the third driving transistor PM5 in the protection circuit is grounded. The second driving transistor NM2 is a MOS device with a low voltage withstand capability (Vds).

[0049] Charge Pump: Provides the gate bias voltage for the first drive transistor HVNM1. The voltage CP_PRE should be greater than the output voltage and the VGS of the first drive transistor HVNM1 to ensure that the first drive transistor HVNM1 is turned on. At the same time, CP_PRE needs to be less than the output voltage and the maximum VGS withstand voltage of the first drive transistor HVNM1 to protect the gate-source terminals from breakdown damage caused by the asymmetrical structure of the high-voltage transistor in the BCD process.

[0050] The protection circuit is used to protect the first driving transistor HVNM1.

[0051] The protection circuit includes a first diode D1 and a third driving transistor PM5.

[0052] Since the output voltage of the charge pump circuit controls the gate of the first driving transistor HVNM1 after passing through a low-pass filter, and the maximum withstand voltage VGS of the high-voltage transistor in the BCD process is limited, to prevent the gate oxide layer of the first driving transistor HVNM1 from being damaged due to excessively high CP_PRE = CP_OUT voltage, a Zener diode D1 and a third driving transistor PM5 are added here as a protection circuit. The gate voltage of the third driving transistor PM5 is the bandgap reference voltage. When the output voltage of the charge pump circuit is too high, and the VGS of the first driving transistor HVNM1 is too large, posing a risk of breakdown, the source voltage of the third driving transistor PM5 is CP_PRE minus a fixed reverse breakdown voltage of transistor D1. When the voltage VGS of the third driving transistor PM5 increases, the third driving transistor PM5 turns on and pulls down the CP_PRE voltage, thereby protecting the gate of the first driving transistor HVNM1.

[0053] The cathode of the first diode D1 is connected to the second output terminal of the charge pump; the anode of the first diode D1 is connected to the source of the third driving transistor PM5; the gate of the third driving transistor PM5 is connected to the bandgap reference voltage; and the drain of the third driving transistor PM5 is grounded.

[0054] The output of the charge pump is connected to the drain of the second driving transistor NM2 and the gate of the first driving transistor HVNM1 through a low-pass filter.

[0055] The low-pass filter is used to filter the output voltage of the charge pump.

[0056] like Figure 1 As shown, the output terminal of the drain of the second driving transistor NM2 is also connected to the second diode D2. The second diode D2 is a Zener diode: its function is to protect the source-drain breakdown voltage of the second driving transistor NM2. Because the second driving transistor NM2 is a low-voltage MOSFET, its source-drain breakdown voltage is usually low. However, even after the CP_OUT voltage is low-pass filtered by the CP_PRE voltage, it may still exceed the maximum Vds breakdown voltage of the second driving transistor NM2. If the CP_OUT voltage is too high, the second diode D2 reaches its reverse breakdown voltage, which can pull down the CP_OUT voltage to protect the second driving transistor NM2 from damage.

[0057] Working principle of the invention:

[0058] like Figure 1 As shown, when the power supply voltage is high, the feedback voltage... When the voltage at the op-amp's output terminal VO1 increases, the second driving transistor NM2 turns on, and current flows from CP_OUT to diode D2 and the second driving transistor NM2 to GND, pulling down the CP_OUT voltage. A negative feedback loop is formed by controlling the gate voltage of the first driving transistor HVNM1: as the VOUT voltage increases, the voltage at the op-amp's positive terminal VFB increases, the voltage at the op-amp's output terminal VO1 increases, and the CP_OUT voltage decreases, resulting in a decrease in the VOUT voltage. This stabilizes the output voltage of the first driving transistor HVNM1. When VBG = VFB, the closed-loop negative feedback is in a stable state, and the VOUT voltage at this time is as follows:

[0059]

[0060] When the power supply voltage is low, the output voltage VOUT is lower than the rated output voltage. Feedback voltage Therefore, the voltage at the output terminal VO1 of the op-amp drops to 0V, and the second driver transistor NM2 is turned off. The gate voltage of the first driver transistor HVNM1 is the fixed voltage output by the charge pump circuit. CP_PRE filters out high-frequency glitches through a low-pass filter composed of the third resistor R3 and the first capacitor C1, resulting in a relatively stable CP_OUT voltage. The first driving transistor HVNM1 operates in the linear region, acting as a switch between the power supply VBAT and VOUT, with the output voltage VOUT equal to the input voltage VBAT.

[0061] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0062] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A low-power adaptive low-voltage high-voltage regulator circuit, characterized in that, The low-power adaptive low-voltage high-voltage regulator circuit includes: an operational amplifier, a driver, and a voltage regulator circuit. The negative input terminal of the operational amplifier is connected to the bandgap reference voltage; the positive terminal of the operational amplifier is used to receive the feedback voltage; the feedback voltage is used to characterize the output voltage of the voltage regulator circuit; the output terminal of the operational amplifier is connected to the first control terminal of the driving device; the output terminal of the driving device is connected to the control terminal of the voltage regulator circuit; the second control terminal of the driving device is connected to the bandgap reference voltage. The operational amplifier is used to transmit a drive signal to the driving device under a first preset condition; the first preset condition is that the feedback voltage is greater than the bandgap reference voltage. The driving device is used to control the voltage regulator circuit based on the driving signal, so that the voltage regulator circuit outputs a stable voltage; The voltage regulator circuit includes: a power supply, a first driving transistor, a first resistor, and a second resistor; the first driving transistor is an NMOS high-voltage transistor, the Vds of the first driving transistor can withstand high voltage, and the high voltage withstand value of the first driving transistor can be adjusted as needed; The driving device includes: a charge pump, a second driving transistor, and a protection circuit; the protection circuit includes a first diode and a third driving transistor; the protection circuit is used to protect the first driving transistor; the third driving transistor is a PMOS transistor with a voltage withstand capability of Vds. The gate of the second driving transistor is connected to the output terminal of the operational amplifier; the output terminal of the charge pump is connected to the drain of the second driving transistor and the gate of the first driving transistor, respectively; the first input terminal of the protection circuit is located between the charge pump and the gate of the first driving transistor; the second input terminal of the protection circuit is connected to the bandgap reference voltage; the drain of the third driving transistor in the protection circuit is grounded.

2. The low-power adaptive low-voltage high-voltage regulator circuit according to claim 1, characterized in that, The driving device specifically includes: Under the second preset condition, when a drive signal is received, the second drive transistor in the drive device is turned on, pulling down the voltage at the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable. Under the second preset condition, when no drive signal is received, the charge pump in the drive device supplies power to the drive terminal of the voltage regulator circuit, so that the output voltage of the voltage regulator circuit is stable. The second preset condition is ; Among them, V OUT This is the output voltage of the voltage regulator circuit; The maximum VGS withstand voltage of the first driving transistor in the voltage regulator circuit; CP PRE The voltage supplied by the driving device to the driving terminal of the voltage regulator circuit; VTH is the voltage of the first driving transistor in the voltage regulator circuit.

3. The low-power adaptive low-voltage high-voltage regulator circuit according to claim 1, characterized in that, The gate of the first driving transistor is connected to the output terminal of the driving device; the drain of the first driving transistor is connected to the power supply; the source of the first driving transistor is connected to one end of the first resistor; the other end of the first resistor is connected to the second resistor; the other end of the second resistor is grounded; the other end of the first resistor is also connected to the positive terminal of the operational amplifier; the source of the first driving transistor serves as the output terminal of the voltage regulator circuit.

4. The low-power adaptive low-voltage high-voltage regulator circuit according to claim 3, characterized in that, The cathode of the first diode is connected to the second output terminal of the charge pump; the anode of the first diode is connected to the source of the third driving transistor; the gate of the third driving transistor is connected to the bandgap reference voltage; and the drain of the third driving transistor is grounded.

5. The low-power adaptive low-voltage high-voltage regulator circuit according to claim 3, characterized in that, The output of the charge pump is connected to the drain of the second driving transistor and the gate of the first driving transistor through a low-pass filter. The low-pass filter is used to filter the output voltage of the charge pump.

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