Output adjustable closed-loop charge pump circuit and method for resisting PVT variation

Abstract

The present invention discloses a closed-loop charge pump circuit and method with adjustable output and resistance to PVT variations. The output method of the closed-loop charge pump circuit with adjustable output and resistance to PVT variations includes step S1: a switching capacitor module obtains the potential of the positive plate of the pump capacitor Cpump through the on-off processing of the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs a boosted output signal VCP; step S2: a PWM modulation module samples the difference between the boosted output signal VCP and the power supply voltage VBB through a difference sampling unit. The closed-loop charge pump circuit and method with adjustable output and resistance to PVT variations disclosed by the present invention can adjust ΔV according to the actual working environment, thereby adjusting the value of the output voltage signal VCP. While achieving adjustable output voltage, the circuit also has PVT-resistant characteristics through compensation technology, and has a wider range of application scenarios.

Description

Technical Field

[0001] The present invention belongs to the technical field of charge pump circuits, and in particular relates to a closed-loop charge pump circuit with adjustable output and resistance to PVT (Process-Voltage-Temperature) variations, and an output method for a closed-loop charge pump circuit with adjustable output and resistance to PVT (Process-Voltage-Temperature) variations. Background Art

[0002] As manufacturing processes continue to shrink, PVT variations are drawing increasing attention. Process deviations caused by fluctuations in process parameters continue to increase, and after chip manufacturing is complete, different chips may be subjected to different process conditions.

[0003] For open-loop charge pump circuits, the output voltage is particularly sensitive to PVT variations, and thus often experiences significant fluctuations due to PVT and other parameters. To stabilize the output voltage, feedback mechanisms are often employed to regulate the output. Common feedback mechanisms include pulse width modulation (PWM), pulse skip modulation (PSM), and input current limiting. However, during design, the required performance is typically guaranteed under worst-case PVT conditions. However, under other circuit conditions, the output voltage may exceed the set voltage. Consequently, robust technologies are becoming increasingly necessary to improve circuit performance and prevent functional failures.

[0004] Different approaches exist in different fields to minimize the performance loss caused by PVT variations. The output transfer function of the entire circuit can be designed to be composed of the capacitance ratio and the transistor size ratio. Given that both capacitance ratio and transistor size ratio are stable under PVT variations, the voltage gain is expected to remain constant. However, this is difficult to achieve in practical applications and often incurs significant hardware overhead. Alternatively, an auxiliary unipolar amplifier can be used to track PVT variations for compensation. While this approach reduces the amplifier's PVT sensitivity, the PVT sensitivity of the switched capacitor circuit remains for charge pump circuits. Alternatively, a PVT detector can be used to monitor the circuit's operating environment and adjust the circuit accordingly.

[0005] To change the output voltage, the charge pump's voltage conversion ratio can be altered to achieve adjustable output voltage. This involves changing the series or parallel connections between the floating capacitors. However, parasitic capacitance reduces conversion efficiency and increases the area required. This is undesirable for charge pumps that use external capacitors.

[0006] Therefore, further improvements are made to the above problems. Summary of the Invention

[0007] The main purpose of the present invention is to provide a closed-loop charge pump circuit and method with adjustable output and resistance to PVT changes. The circuit can adjust ΔV according to the actual working environment, and then adjust the value of the output voltage signal VCP. While achieving adjustable output voltage, the circuit is made resistant to PVT changes through compensation technology, and has a wider range of application scenarios.

[0008] Another object of the present invention is to provide a closed-loop charge pump circuit and method with adjustable output and resistance to PVT variations. Pulse width modulation is used to change the duty cycle of each operating cycle by varying the reference voltage value of the comparator while maintaining the frequency constant, thereby controlling the energy transfer in each charge and discharge cycle and thereby adjusting the output voltage. After setting the desired output voltage, the temperature sensor module and the process angle detection module are used to determine the chip temperature and process angle at which the chip is operating. The control signal then selects different reference voltage values in a lookup table to obtain a stable output voltage signal VCP that is resistant to PVT variations.

[0009] To achieve the above objectives, the present invention provides an output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variations, comprising the following steps:

[0010] Step S1: The switched capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs a boosted output signal VCP;

[0011] Step S2: The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit.

[0012] Step S3: The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage (VCP) requirement and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

[0013] As a further preferred technical solution of the above technical solution, step S1 is specifically implemented as follows:

[0014] Step S1.1: Turning on the switch tubes MN1 and MN2 of the switch tube unit and turning off the switch tubes MP1 and MP2 to charge the pump capacitor Cpump, thereby making the potential of the positive plate of the pump capacitor Cpump equal to the potential VBB of the power supply voltage VBB;

[0015] Step S1.2: In the next cycle, the switch tubes MN1 and MN2 of the switch tube unit are turned off and the switch tubes MP1 and MP2 are turned on, so that the pump capacitor Cpump is charged, so that the potential of the negative plate of the pump capacitor Cpump is VBB and the potential of the positive plate is VBB+ΔV;

[0016] Step S1.3: Transfer the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boosted output signal VCP to the load resistor RL.

[0017] As a further preferred technical solution of the above technical solution, in step S2, for the temperature compensation unit:

[0018] V of transistor Q1 BE Generates a current signal V BE / R1, the current signal size sampled at the same time is (VCP-VBB-V BE ) / R2, if R1=R2, the temperature change of the signal at the positive input terminal of the comparison output unit is offset.

[0019] As a further preferred technical solution of the above technical solution, in step S3, for the comparison output unit:

[0020] When the voltage signal Vin is greater than the reference voltage Vref, the comparator U4 of the comparison output unit outputs a high level. When the voltage signal Vin is less than the reference voltage Vref, the comparator U4 outputs a low level. The comparison signal Vout and the clock signal CLK are input to the logic module together, thereby changing the duty cycle of the clock signal CLK. The pulse signal Vpulse output by the logic module is transmitted to the switch tubes MN1, MN2, MP1, and MP2 respectively, thereby performing charging and discharging.

[0021] The rising edge of the comparison signal Vout of the comparator U4 determines the rising edge of the pulse signal Vpulse, and the falling edge of the clock signal CLK determines the falling edge of the pulse signal Vpulse. When the voltage is first boosted, the duty cycle of the pulse signal Vpulse is relatively small, thereby controlling the switching tube unit to charge. After stabilization, the duty cycle of the pulse signal Vpulse is relatively large, thereby controlling the switching tube unit to discharge. The sampled output voltage change is finally fed back to the switching tube unit to control the conduction state of the switching tube unit to maintain the stability of the boost output signal VCP.

[0022] As a further preferred technical solution of the above technical solution, in step S3, for the output voltage modulation module:

[0023] The output voltage modulation module includes a decoder U1, a temperature sensor U2, and a process angle detector U3. The module selects the difference between the charge pump's boosted output signal VCP and the power supply voltage VBB via external pins A1 and A2. When A1A2 = 00, ΔV is selected as a first voltage value (preferably 5V). When A1A2 = 01, ΔV is selected as a second voltage value (preferably 7V). When A1A2 = 10, ΔV is selected as a third voltage value (preferably 10V). The module also determines the chip's temperature and process angle based on the temperature sensor U2 and process angle detector U3. The module then controls the signal to select different reference voltages Vref in the lookup table, thereby obtaining a boosted output signal VCP that is resistant to PVT variations and stable.

[0024] The process angle detector U3 includes several all-P-type switching tubes. The low level of the odd-numbered stages will increase as the number of stages increases. Under different processes, Vn+1>Vn>Vn-1 always exists. Therefore, the output signals of the n-1th stage, nth stage and n+1th stage are output to three comparators, where:

[0025] When the process angle is ff, the three comparators output 111. When the process angle is tt, comparator A1 outputs a pulse signal, comparator A2 and comparator A3 output 11. When the process angle is ss, comparator A1 and comparator A2 output pulse signals, and comparator A3 outputs 1.

[0026] The output ends of the three comparators are all connected to the encoding module for encoding. The encoding module counts the rising edges of the input signal. In order to prevent false triggering and leave a certain margin, when the number of rising edges is greater than the preset value (preferably 7), it outputs a low level. When the number of rising edges is less than the preset value, it outputs a high level, and then judges the process angle of the current chip. When the output signal of the encoding module is 100, it corresponds to the ff process angle, when the output signal is 010, it corresponds to the tt process angle, and when the output signal is 001, it corresponds to the ss process angle.

[0027] To achieve the above objectives, the present invention further provides a closed-loop charge pump circuit with adjustable output and resistance to PVT variations, comprising a switched capacitor module, a PWM modulation module, and an output voltage modulation module, wherein:

[0028] The switch capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boost output signal VCP;

[0029] The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit.

[0030] The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage (VCP) requirement and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

[0031] The beneficial effects of the present invention are:

[0032] The present invention primarily sets the difference between the charge pump's output voltage and the power supply voltage according to different operating environments, and changes the amplifier's reference voltage value according to a pre-set lookup table, thereby changing the charge on the pump capacitor. Simultaneously, a temperature sensor and a process angle detector detect the temperature and process angle, fine-tuning the reference voltage value to obtain a stable output voltage signal VCP, effectively providing energy for subsequent loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the output adjustable closed-loop charge pump circuit and method for resisting PVT variation of the present invention.

[0034] Figure 2 It is a modulation timing diagram of the output adjustable closed-loop charge pump circuit and method for resisting PVT variation of the present invention.

[0035] Figure 3 It is a process angle detection circuit diagram of a process angle detector of the output adjustable closed-loop PVT variation resistant charge pump circuit and method of the present invention. DETAILED DESCRIPTION

[0036] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are for illustrative purposes only, and those skilled in the art will readily appreciate other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0037] In the preferred embodiment of the present invention, those skilled in the art should note that the power supply voltage and the lookup table unit involved in the present invention may be regarded as prior art.

[0038] Preferred embodiment.

[0039] The present invention discloses an output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation, comprising the following steps:

[0040] Step S1: The switched capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs a boosted output signal VCP;

[0041] Step S2: The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit.

[0042] Step S3: The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage (VCP) requirement and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

[0043] Specifically, step S1 is implemented as follows:

[0044] Step S1.1: Turning on the switch tubes MN1 and MN2 of the switch tube unit and turning off the switch tubes MP1 and MP2 to charge the pump capacitor Cpump, thereby making the potential of the positive plate of the pump capacitor Cpump equal to the potential VBB of the power supply voltage VBB;

[0045] Step S1.2: In the next cycle, the switch tubes MN1 and MN2 of the switch tube unit are turned off and the switch tubes MP1 and MP2 are turned on, so that the pump capacitor Cpump is charged, so that the potential of the negative plate of the pump capacitor Cpump is VBB and the potential of the positive plate is VBB+ΔV;

[0046] Step S1.3: Transfer the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boosted output signal VCP to the load resistor RL.

[0047] More specifically, in step S2, for the temperature compensation unit:

[0048] V of transistor Q1 BE Generates a current signal V BE / R1, the current signal size sampled at the same time is (VCP-VBB-V BE ) / R2, if R1=R2, the temperature change of the signal at the positive input terminal of the comparison output unit is offset.

[0049] Furthermore, in step S3, for the comparison output unit:

[0050] When the voltage signal Vin is greater than the reference voltage Vref, the comparator U4 of the comparison output unit outputs a high level. When the voltage signal Vin is less than the reference voltage Vref, the comparator U4 outputs a low level. The comparison signal Vout and the clock signal CLK are input to the logic module together, thereby changing the duty cycle of the clock signal CLK. The pulse signal Vpulse output by the logic module is transmitted to the switch tubes MN1, MN2, MP1, and MP2 respectively, thereby performing charging and discharging.

[0051] The rising edge of the comparison signal Vout of the comparator U4 determines the rising edge of the pulse signal Vpulse, and the falling edge of the clock signal CLK determines the falling edge of the pulse signal Vpulse. When the voltage is first boosted, the duty cycle of the pulse signal Vpulse is relatively small, thereby controlling the switching tube unit to charge. After stabilization, the duty cycle of the pulse signal Vpulse is relatively large, thereby controlling the switching tube unit to discharge. The sampled output voltage change is finally fed back to the switching tube unit to control the conduction state of the switching tube unit to maintain the stability of the boost output signal VCP.

[0052] Furthermore, in step S3, for the output voltage modulation module:

[0053] The output voltage modulation module includes a decoder U1, a temperature sensor U2, and a process angle detector U3. The module selects the difference between the charge pump's boosted output signal VCP and the power supply voltage VBB via external pins A1 and A2. When A1A2 = 00, ΔV is selected as a first voltage value (preferably 5V). When A1A2 = 01, ΔV is selected as a second voltage value (preferably 7V). When A1A2 = 10, ΔV is selected as a third voltage value (preferably 10V). The module also determines the chip's temperature and process angle based on the temperature sensor U2 and process angle detector U3. The module then controls the signal to select different reference voltages Vref in the lookup table, thereby obtaining a boosted output signal VCP that is resistant to PVT variations and stable.

[0054] The process angle detector U3 includes several all-P-type switching tubes. The low level of the odd-numbered stages will increase as the number of stages increases. Under different processes, Vn+1>Vn>Vn-1 always exists. Therefore, the output signals of the n-1th stage, nth stage and n+1th stage are output to three comparators, where:

[0055] When the process angle is ff, the three comparators output 111. When the process angle is tt, comparator A1 outputs a pulse signal, comparator A2 and comparator A3 output 11. When the process angle is ss, comparator A1 and comparator A2 output pulse signals, and comparator A3 outputs 1.

[0056] The output ends of the three comparators are all connected to the encoding module for encoding. The encoding module counts the rising edges of the input signal. In order to prevent false triggering and leave a certain margin, when the number of rising edges is greater than the preset value (preferably 7), it outputs a low level. When the number of rising edges is less than the preset value, it outputs a high level, and then judges the process angle of the current chip. When the output signal of the encoding module is 100, it corresponds to the ff process angle, when the output signal is 010, it corresponds to the tt process angle, and when the output signal is 001, it corresponds to the ss process angle.

[0057] The present invention also discloses a closed-loop charge pump circuit with adjustable output and resistance to PVT changes, comprising a switching capacitor module, a PWM modulation module and an output voltage modulation module, wherein:

[0058] The switch capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boost output signal VCP;

[0059] The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit.

[0060] The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage (VCP) requirement and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

[0061] The switched capacitor module includes a pump capacitor Cpump and a switch tube unit, the pump capacitor Cpump and the switch tube unit are electrically connected, the pump capacitor Cpump is connected to a load capacitor CL through the switch tube unit, and the load capacitor CL is used to output a boost output signal VCP;

[0062] The PWM modulation module includes a difference sampling unit, a temperature compensation unit and a comparison output unit, wherein the first input terminal of the difference sampling unit inputs the boost output signal VCP and the second input terminal of the difference sampling unit inputs the power supply voltage VBB, the output terminal of the temperature compensation unit is electrically connected to the compensation terminal of the difference sampling unit, and the output terminal of the difference sampling unit is electrically connected to the positive input terminal of the comparison output unit, and the output terminal of the comparison output unit is electrically connected to the input terminal (gate) of the switch tube unit;

[0063] The voltage modulation module includes a decoder U1, a temperature sensor U2 and a process angle detector U3. The temperature sensor U2 and the process angle detector U3 are electrically connected to the input end of the decoder U1 respectively, and the output end of the decoder U1 (through the lookup table unit) is electrically connected to the negative input end of the comparison output unit.

[0064] Specifically, the switch tube unit includes a switch tube MP1, a switch tube MP2, a switch tube MN1 and a switch tube MN2, wherein:

[0065] The common terminal of the drain of the switch transistor MP1 and the drain of the switch transistor MN1 is electrically connected to the negative plate of the pump capacitor Cpump, and the common terminal of the source of the switch transistor MP2 and the drain of the switch transistor MN2 is electrically connected to the positive plate of the pump capacitor Cpump;

[0066] The source of the switch tube MP1 and the source of the switch tube MN2 are both connected to the power supply voltage VBB, and the drain of the switch tube MP2 is connected to the load capacitor CL and the load resistor RL respectively.

[0067] More specifically, the difference sampling unit includes a switch tube MP4, a switch tube MP5, and a switch tube MP6, wherein:

[0068] The boost output signal VCP is input to the common terminal of the source of the switch tube MP4 and the source of the switch tube MP5 and is also electrically connected to one end of the resistor R2. The other end of the resistor R2 (the end away from the common terminal) is electrically connected to the collector of the transistor Q4, and the collector and base of the transistor Q4 are electrically connected.

[0069] The common terminal of the gate of the switching transistor MP4 and the gate of the switching transistor MP5 is electrically connected to the collector of the transistor Q3, the emitter of the transistor Q3 and the emitter of the transistor Q4 are both electrically connected to the gate of the switching transistor MP6, and the base of the transistor Q3 is electrically connected to the base of the transistor Q4;

[0070] The source of the switch tube MP6 is electrically connected to the drain of the switch tube MP4 , and the drain of the switch tube MP6 is grounded via the resistor R3 and the resistor R4 in sequence.

[0071] Furthermore, the temperature compensation unit includes a transistor Q1 and a resistor R1, wherein:

[0072] The collector of the transistor Q1 is connected to the operating current Ib on one path and is electrically connected to the base of the transistor Q2 on the other path. A resistor R1 is connected between the emitter and base of the transistor Q1 and the base of the transistor Q1 is electrically connected to the emitter of the transistor Q2.

[0073] The collector of the transistor Q2 is electrically connected to the drain and gate of the switch tube MP7, the gate of the switch tube MP7 is electrically connected to the gate of the switch tube MP3, and the drain of the switch tube MP3 is electrically connected to the drain of the switch tube MP6 (the circuit signal V is obtained by the mirror image of the circuit). BE / R1).

[0074] Furthermore, the comparison output unit includes a comparator U4 and a logic module U5, wherein:

[0075] The common end of the resistor R3 and the resistor R4 is electrically connected to the positive input end of the comparator U4, and the output end of the comparator U4 is electrically connected to the first input end of the logic module U5, and the second input end of the logic module U5 inputs the clock signal CLK. The output end of the logic module U5 is respectively electrically connected to the gate of the switch tube MP1 (through the drive circuit Driver1), the gate of the switch tube MP2 (through the drive circuit Driver4), the gate of the switch tube MN1 (through the drive circuit Driver2), and the gate of the switch tube MN2 (through the drive circuit Driver3).

[0076] Preferably, the decoder U1 includes an external pin A1 and an external pin A2.

[0077] The principle of the present invention is:

[0078] Including switch capacitor module, PWM modulation module and output voltage modulation module, such as Figure 1 shown.

[0079] The switched capacitor module works as follows: First, switches MN1 and MN2 are turned on, while switches MP1 and MP2 are turned off, charging the pump capacitor Cpump. The positive plate of the pump capacitor reaches VBB, while the negative plate reaches 0. Utilizing the characteristic that the voltage on the capacitor cannot change suddenly, in the next cycle, switches MN1 and MN2 are turned off, while switches MP1 and MP2 are turned on. The negative plate of the pump capacitor reaches VBB, and the positive plate reaches VBB + ΔV. The charge on the capacitor is then transferred to the load capacitor, generating a boosted output signal, VCP.

[0080] Next, the proposed charge pump circuit adopts pulse width modulation. The working process of the PWM modulation module is as follows: first, the difference between the output voltage signal VCP of the charge pump and the power supply voltage VBB is sampled, the voltage difference is converted into a current signal, and then divided by resistors to convert it into a voltage signal Vin and output it to the positive terminal Vin of the comparator. BE The generated current signal will be introduced with temperature characteristics, so it needs to be temperature compensated. BE Generates a current signal V BE / R1, the current signal sampled at the same time is (VCP-VBB-VBE) / R2. If R1=R2, the temperature change of the positive terminal signal of the comparator can be offset. This voltage signal is transmitted to the positive terminal of the comparator, and the negative terminal is the reference voltage signal. Different reference voltages can be selected according to the reference voltage lookup table unit. The specific voltage value of the lookup table is controlled by the external input A1 and A2 pin signals, the temperature sensor and the process angle detector. When Vin is greater than Vref, a high level is output. When Vin is less than Vref, a low level is output. The comparison result and the clock signal CLK are input into the logic module together to change the duty cycle of the clock signal. The output pulse signal Vpulse is transmitted to the four switch tubes for charging and discharging. The modulation process timing diagram is as follows Figure 2 As shown in the figure, the rising edge of Vout determines the rising edge of Vpulse, while the falling edge of CLK determines the falling edge of Vpulse. Initially, during the boost phase, the duty cycle of the Vpulse signal is small, primarily controlling the charging of the switch. After stabilization, the duty cycle of the Vpulse signal increases, primarily controlling the discharging of the switch. The sampled output voltage changes are ultimately fed back to the switch to control its conduction state and maintain output voltage stability.

[0081] The output voltage modulation module is a combination of a decoder and a PVT detection module. External pins A1 and A2 select the difference between the charge pump's output voltage and the power supply voltage. For example, when A1A2 = 00, ΔV = 5V; when A1A2 = 01, ΔV = 7V; and when A1A2 = 10, ΔV = 10V. The temperature sensor module and process angle detector simultaneously determine the chip's current temperature and process angle. The control signal then selects different Vref values in a lookup table, generating a stable output voltage signal (VCP) that is resistant to PVT fluctuations.

[0082] The PVT detection module includes a temperature sensor module and a process angle detector. Figure 3As shown, using all P-type transistors, the low-level voltage of odd-numbered stages increases with the number of stages. Under different process technologies, Vn+1>Vn>Vn-1 is always the case. Therefore, the output signals of stages n-1, n, and n+1 are fed to three comparator circuits. At the ff angle, the three comparator circuits output 111. At the tt angle, comparator A1 outputs a pulse signal, while comparators A2 and A3 output 11. At the ss angle, comparators A1 and A2 output a pulse signal, while comparator A3 outputs 1. These signals are then fed to the subsequent encoding module for encoding. The encoding module counts the rising edges of the input signal, preventing false triggering while leaving a margin. When the number of rising edges is greater than 7, a low level is output, and when the number is less than 7, a high level is output, thereby determining the process angle of the current chip. When the output signal C[2:0] of the encoding module is 100, it corresponds to the ff process angle, when the output signal C[2:0] is 010, it corresponds to the tt process angle, and when the output signal C[2:0] is 001, it corresponds to the ss process angle.

[0083] Because circuits are inevitably affected by temperature, the impact of temperature is often greater than that of process angle, resulting in overlapping temperature effects when detecting process angles. Therefore, segmented temperature detection is necessary. Different VRs are selected for comparison in different temperature segments to ensure that the comparator output signal remains consistent across different process angles. This allows for distinguishing between different process angles from -40°C to 135°C.

[0084] It is worth mentioning that the technical features such as the power supply voltage and lookup table unit involved in the patent application of this invention should be regarded as prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected by conventional choices in the field and should not be regarded as the inventive point of the patent of this invention. The patent of this invention will not be further elaborated.

[0085] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation, characterized in that: The following steps are involved: Step S1: The switched capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs a boosted output signal VCP; Step S2: The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit. Step S3: The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage requirement and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

2. The output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation according to claim 1, characterized in that: Step S1 is specifically implemented as follows: Step S1.1: Turning on the switch tubes MN1 and MN2 of the switch tube unit and turning off the switch tubes MP1 and MP2 to charge the pump capacitor Cpump, thereby making the potential of the positive plate of the pump capacitor Cpump equal to the potential VBB of the power supply voltage VBB; Step S1.2: In the next cycle, the switch tubes MN1 and MN2 of the switch tube unit are turned off and the switch tubes MP1 and MP2 are turned on, so that the pump capacitor Cpump is charged, so that the potential of the negative plate of the pump capacitor Cpump is VBB and the potential of the positive plate is VBB+ΔV; Step S1.3: Transfer the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boosted output signal VCP to the load resistor RL.

3. The output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation according to claim 2, characterized in that: In step S2, for the temperature compensation unit: V of transistor Q1 BE Generates a current signal V BE / R1, the current signal size sampled at the same time is (VCP-VBB-V BE ) / R2, if R1=R2, the temperature change of the signal at the positive input terminal of the comparison output unit is offset.

4. The output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation according to claim 3, characterized in that: In step S3, for the comparison output unit: When the voltage signal Vin is greater than the reference voltage Vref, the comparator U4 of the comparison output unit outputs a high level. When the voltage signal Vin is less than the reference voltage Vref, the comparator U4 outputs a low level. The comparison signal Vout and the clock signal CLK are input to the logic module together, thereby changing the duty cycle of the clock signal CLK. The pulse signal Vpulse output by the logic module is transmitted to the switch tubes MN1, MN2, MP1, and MP2 respectively, thereby performing charging and discharging. The rising edge of the comparison signal Vout of the comparator U4 determines the rising edge of the pulse signal Vpulse, and the falling edge of the clock signal CLK determines the falling edge of the pulse signal Vpulse. When the voltage is first boosted, the duty cycle of the pulse signal Vpulse is relatively small, thereby controlling the switching tube unit to charge. After stabilization, the duty cycle of the pulse signal Vpulse is relatively large, thereby controlling the switching tube unit to discharge. The sampled output voltage change is finally fed back to the switching tube unit to control the conduction state of the switching tube unit to maintain the stability of the boost output signal VCP.

5. The output method of a closed-loop charge pump circuit with adjustable output and resistance to PVT variation according to claim 4, characterized in that: In step S3, for the output voltage modulation module: The output voltage modulation module includes a decoder U1, a temperature sensor U2, and a process angle detector U3. The module selects the difference between the charge pump's boosted output signal VCP and the power supply voltage VBB via external pins A1 and A2. When A1A2 = 00, ΔV is selected as the first voltage value; when A1A2 = 01, ΔV is selected as the second voltage value; and when A1A2 = 10, ΔV is selected as the third voltage value. The module also determines the chip's current temperature and process angle based on the temperature sensor U2 and process angle detector U3. The module then controls the signal to select different reference voltages Vref in the lookup table, thereby obtaining a boosted output signal VCP that is resistant to PVT variations and stable. The process angle detector U3 includes several all-P-type switching tubes. The low level of the odd-numbered stages will increase as the number of stages increases. Under different processes, Vn+1>Vn>Vn-1 always exists. Therefore, the output signals of the n-1th stage, nth stage and n+1th stage are output to three comparators, where: When the process angle is ff, the three comparators output 111. When the process angle is tt, comparator A1 outputs a pulse signal, comparator A2 and comparator A3 output 11. When the process angle is ss, comparator A1 and comparator A2 output pulse signals, and comparator A3 outputs 1. The output ends of the three comparators are all connected to the encoding module for encoding. The encoding module counts the rising edges of the input signal. In order to prevent false triggering and leave a certain margin, when the number of rising edges is greater than the preset value, it outputs a low level. When the number of rising edges is less than the preset value, it outputs a high level, and then judges the process angle of the current chip. When the output signal of the encoding module is 100, it corresponds to the ff process angle, when the output signal is 010, it corresponds to the tt process angle, and when the output signal is 001, it corresponds to the ss process angle.

6. A closed-loop charge pump circuit with adjustable output and resistance to PVT variations, applied to the output method of the closed-loop charge pump circuit with adjustable output and resistance to PVT variations according to any one of claims 1 to 5, characterized in that: It includes a switched capacitor module, a PWM modulation module and an output voltage modulation module, wherein: The switch capacitor module obtains the potential of the positive plate of the pump capacitor Cpump by turning on and off the switch tube unit and transfers the charge of the pump capacitor Cpump to the load capacitor CL, so that the load capacitor CL outputs the boost output signal VCP; The PWM modulation module samples the difference between the boost output signal VCP and the power supply voltage VBB through the difference sampling unit, thereby converting the sampled difference into a current signal and obtaining a voltage signal Vin input to the positive input terminal of the comparison output unit through resistor voltage division. The temperature compensation unit also compensates for the temperature characteristics introduced by the current signal generated by the difference sampling unit. The output voltage modulation module selects different reference voltages Vref through the lookup table unit according to the output voltage requirements and transmits the reference voltage Vref to the negative input terminal of the comparison output unit, so that the reference voltage Vref is compared with the voltage signal Vin, thereby outputting a pulse signal Vpulse to feed back to the switch tube unit, thereby controlling the conduction state of the switch tube unit, and finally maintaining the stability of the boost output signal VCP through closed-loop regulation.

Images