CN113746325A - Charge pump with adaptive charge compensation for image sensor - Google Patents
Charge pump with adaptive charge compensation for image sensor Download PDFInfo
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- H—ELECTRICITY
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- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
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- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
- H04N25/62—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
- H04N25/625—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels for the control of smear
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Abstract
The invention relates to an analog integrated circuit, which is applied to a charge pump with self-adaptive charge compensation of an image sensor and aims to accelerate the recovery of the output voltage of the charge pump and ensure the normal work of pixels. The output end of the LDO is connected with an output capacitor Cout，CoutThe other end is grounded, and the output voltage is Vout. Vout provides gate bias voltage for all TG of a row of pixels in the pixel array at the same time, and the self-adaptive charge compensation circuit dynamically adjusts the SC CP according to the state of the output voltage of the SC CP, so that the output voltage is recovered to a rated value. The invention is mainly applied to the design and manufacture occasions of the analog integrated circuit.
Description
Technical Field
The invention relates to the field of analog integrated circuit design, in particular to application of driving an image sensor pixel by a charge pump. The recovery of the output voltage is accelerated by dynamically compensating the charge pump through the self-adaptive charge compensation circuit.
Background
Domestic and foreign researches show that the performance of the image sensor under the condition of extremely weak ambient light can be effectively improved by adjusting the Gate voltage of a transmission Tube (TG) in an active pixel. When the grid voltage of the transmission tube adopts high voltage, the charge transfer can be accelerated, the charge transfer efficiency is effectively improved, and the image trailing condition is improved. When the charge pump supplies power to the outside by using the charges stored in the output capacitor, the TG gate voltage of the pixel transmission tube is periodically inverted, so that charge redistribution occurs between the output capacitor of the charge pump and the TG gate capacitor of the pixel array, and the high voltage output by the charge pump is reduced. To ensure proper operation of the pixel, the output voltage needs to be restored to the nominal value within one row selection period. The invention provides a charge pump with a self-adaptive charge compensation mechanism, which can effectively shorten the recovery time of output voltage theoretically and meet the working requirement of pixels.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a charge pump with a self-adaptive charge compensation function, so that the recovery of the output voltage of the charge pump is accelerated, and the normal work of pixels is ensured. Therefore, the invention adopts the technical scheme that the charge pump with the adaptive charge compensation, which is applied to the image sensor, comprises a switched capacitor charge pump SC CP (Switch capacitor charge pump), a Low Dropout linear Regulator (Low drop Regulator LDO) and an adaptive charge compensation circuit. The SC CP is a voltage-multiplying charge pump, the output filter capacitor is a structure formed by connecting capacitors C1 and C2 in series, the series node is mod1, and the output voltage Vcp of the SC CP is connected to a load circuit after being subjected to voltage stabilization processing through a Low Dropout Regulator (LDO). The output end of the LDO is connected with an output capacitor Cout，CoutThe other end is grounded, and the output voltage is Vout. Vout provides the gate bias voltage for all TGs in a row of pixels in the pixel array at the same time, so the load capacitance Cload of the charge pump is the sum of the gate parasitic capacitances of all TGs in a row of pixels; when the gate voltage of TG is switched from low level to high level, TG is conducted, and load capacitor CloadAnd output capacitor CoutConnected, adaptive charge compensation circuit based on SThe state of the output voltage of the cpcp dynamically adjusts the SC CP to restore the output voltage to a rated value.
The adaptive charge compensation circuit comprises shunt resistors R1 And R2, a comparator Cmp, AND gates And1, And2, And3, inverters inv1 And inv2, And transmission gates TGa And TGb. The output voltage Vcp of the SC CP is grounded through serially connected resistors R1 and R2, meanwhile, the Vcp is connected to the LDO through another branch, a node mod2 connected with the resistors R1 and R2 is connected with one input end of the comparator cmp, and the other input end of the comparator cmp is connected with a signal VrefAn output signal V of the comparator Cmpref_outnThe And master clock signal Clk is anded with the And gate And1 to generate Clk which clocks the SC CP, And two output signals V of the comparator Cmpref_outAnd Vref_outnRespectively AND with VTG And VTGn through AND gates And2 And And3 to generate signals Va And Vb, which are respectively connected to inverters inv1 And inv2 to generate signals Van And Vbn, wherein Va And Van are control signals of a transmission gate TGa, Vb And Vbn are control signals of TGb, And TGa is responsible for controlling a current IUTGb is responsible for controlling the current IDTGa is connected in series with TGb, and the other end of TGa generates IUIs connected to the output of SC CP, and the other end of TGb is connected to generate IDThe current source is grounded, a serial node of the TGa and the TGb is connected with a mod1 node, and the self-adaptive charge compensation circuit dynamically adjusts the SC CP according to the state of the output voltage Vcp of the SC CP, so that on one hand, the clock signal of the SC CP is modulated, the output voltage of the SC CP is stabilized, and the circuit instability caused by overhigh voltage is prevented; on the other hand, when Vcp and Vout are due to CloadAnd CoutWhen voltage drop is generated by charge exchange, the charge is compensated for an output filter capacitor of the SC CP, namely for C1 and C2, so that the transient performance reduction of the LDO caused by Vcp undershoot is prevented; the charge compensation node is mod1, the node is driven by the current IUIs charge compensated and is driven by a current IDPerforming charge release on the glass; i isUControlled by transmission gate TGa, IDControlled by a transmission gate TGb, when the TG gate voltage is switched from low level to high level, Vcp and Vout generate voltage drop, at the moment, the transmission gate TGb is cut off, TGa is conducted, IUCharge compensation is performed on node mod 1; when Vout recovers the initial voltage level and maintains it for a while, the TG gate voltage goes from highThe voltage is switched to low voltage, TG is switched off, transmission gate TGa is switched off, transmission gate TGb is switched on, IDDischarge C1, C2 in preparation for the Vout drop for the next cycle.
Control signal V of transmission pipe TGTGComparator output signal Vref_outnAnd Vref_outThe timing of the transmission gate control signals Va and Vb is as follows: vTGGoes high at time t1, VTGnGoes to low level, CloadAnd CoutThe voltage drop of Vout will occur due to charge redistribution, the LDO circuit will start to regulate Vout, it needs to pump charge from the voltage-doubling charge pump, but the charge cannot be transferred instantaneously, so VCPA brief overshoot is generated, at which time the output voltage V of the comparatorref_outnGoes low and masks the clock input to stabilize VCPDuring this period Vref_out is high, and VTGPerforming a logical AND operation to generate signals Va, Va being high and Van being low, so that control IUThe transfer gate TGa is turned on to charge the C1 and C2, thereby accelerating the recovery of Vout. At the same time, due to Vref_outnLow, Vb is low, Vbn is high, and transmission gate TGb is off. Vout reverts to a stable initial level at time t2, at which point Vref_outChange to low level, Vref_outnVa is high, Va is switched from high to low, but V is lowTGnIs low, so Vb is still low, Vbn is high, IDAnd the transistor is still cut off by the transmission gate, so that the stability of the Vout in the turn-on stage of the pixel transmission transistor TG is ensured. time t3, VTGOff, VTGnGoes high, VTGGoes low when Va goes low, resulting in IUAnd (6) cutting off. The LDO circuit does not need to draw charge, V, from the SC CP at this timeCPWill enter a self-adaptive adjustment phase, Vref_outnIs no longer VTGnA mask, Vb and Vbn are intermittently switched between low and high levels, and Vref_outnWhen the transmission gate TGb is opened intermittently, the filter capacitors C1 and C2 pass through IDGradually discharging, and finishing the discharging before the next row selection period, wherein the process ensures that Vout is discharged in the process of dischargingThe stability of (2).
The circuit structure adopted by the SC CP charge pump is as follows, switches Switch1, Switch2, Switch3 and Switch4, wherein control signals of the four switches are clk, clkn and clk respectively; pump capacitor Cpump and output filter capacitor CCP_outWherein the charge pump outputs a filter capacitor CCP_outThe input voltage is SC CP, and the input voltage is VIN formed by connecting capacitors C1 and C2 in series.
The LDO circuit structure includes an error amplifier EA, shunt resistors R3 and R4, and a power transistor Mp. The source end of the power tube Mp is connected with Vcp, the drain end is connected with R3 and R4 in series and then grounded, and the voltage of the connection node of R3 and the Mp drain is the output voltage Vout. Vout is divided by the resistors R3 and R4 to return the voltage of the connection node of the two resistors to the positive end of the operational amplifier, and the negative end of the operational amplifier is connected with a preset reference voltage Vref_LDOThe output end of the operational amplifier is connected with MPThe gate, through a negative feedback mechanism, changes the current flowing through R3 and R4, clamping the Vout voltage to the desired voltage value.
The invention has the characteristics and beneficial effects that:
after the pixel exposure is finished, the transmission tube TG is started to transfer photo-generated electrons, the grid voltage of the TG is switched from a low level to a high level, but the grid parasitic capacitance does not store charges and can generate charge exchange with the output capacitance of the charge pump, so that the output voltage Vout of the charge pump generates periodic fluctuation.
Description of the drawings:
FIG. 1TG schematic diagram of the working mode
Fig. 2 is a schematic diagram of an adaptive charge compensated charge pump.
FIG. 3VTG、VTGnControl timing and Vref_out、Vref_outnVa, Vb operating sequence.
Fig. 4SC CP circuit schematic.
FIG. 5 is a schematic diagram of an LDO circuit.
Detailed Description
FIG. 1 shows a schematic diagram of the operation of TG including a clamped Photodiode (Pinned Photodiode PPD) and a transfer tube TG, where after PPD exposure is complete, the transfer of photogenerated electrons begins, at which point VTGWhen the level is changed to high level, the TG conducts the photo-generated electrons to be transferred out through the TG, and when the photo-generated electrons are completely transferred, V isTGGoes low and TG is turned off.
Fig. 2 shows a schematic diagram of a charge pump with adaptive charge compensation, which includes a switched capacitor charge pump SC CP (Switch capacitor charge pump), a Low Dropout linear Regulator (Low drop Regulator LDO), and an adaptive charge compensation circuit. The SC CP is a voltage-multiplying charge pump, the output filter capacitor is a structure formed by connecting capacitors C1 and C2 in series, the series node is mod1, and the output voltage Vcp of the SC CP is connected to a load circuit after being subjected to voltage stabilization processing through a Low Dropout Regulator (LDO). The output end of the LDO is connected with an output capacitor Cout，CoutThe other end is grounded, and the output voltage is Vout. Vout provides the gate bias voltage for all TG of a row of pixels in the pixel array, so the load capacitance C of the charge pumploadIs the sum of the gate parasitic capacitances of all TGs of a row of pixels; when the gate voltage of TG is switched from low level to high level, TG is conducted, and load capacitor CloadAnd output capacitor CoutConnected but due to CloadDoes not store charge, so will be associated with CoutThe charge is redistributed, so that the output voltage Vout of the low dropout regulator LDO is reduced, and the output voltage Vcp of the SC CP is reduced to influence the transient performance of the LDO. The adaptive charge compensation circuit comprises shunt resistors R1 And R2, a comparator Cmp, AND gates And1, And2, And3, inverters inv1 And inv2, And transmission gates TGa And TGb. The output voltage Vcp of the SC CP is grounded through the series-connected resistors R1 and R2, and meanwhile, the Vcp is connected into the LDO through the other branch. The node mod2 connected with the resistors R1 and R2 is connected with one input end of the comparator cmp, and the other input end of the comparator cmp is connected with a signal Vref. An output signal V of the comparator Cmpref_outnAND the master clock signal Clk through an AND gate And1The operation generates clk, which clocks the SC CP. In addition, two output signals V of the comparator Cmpref_outAnd Vref_outnAnd the signals Va And Vb generated by AND2 And And3 with VTG And VTGn respectively are connected to inverters inv1 And inv2 respectively to generate signals Van And Vbn. Va, Van are control signals of transmission gate TGa, and Vb and Vbn are control signals of TGb. TGa is responsible for controlling the current IUTGb is responsible for controlling the current ID. TGa is connected in series with TGb, and the other end of TGa generates IUIs connected to the output of SC CP, and the other end of TGb is connected to generate IDThen to ground, and the series node of TGa and TGb is connected to the mod1 node. The adaptive charge compensation circuit outputs a voltage V of a node according to the SC CPCPDynamically controls the transmission gates TGa and TGb. The self-adaptive charge compensation circuit dynamically adjusts the SC CP according to the state of the output voltage of the SC CP, so that on one hand, the clock signal of the SC CP is modulated, the output voltage of the SC CP is stabilized, and the instability of the circuit caused by overhigh voltage is prevented; on the other hand, when Vcp and Vout are due to CloadAnd CoutWhen voltage drop is generated by charge exchange, the charge can be compensated for the output filter capacitor of the SC CP in time, namely for the C1 and the C2, and the transient performance reduction of the LDO caused by Vcp undershoot is prevented. The charge compensation node is mod1, the node is driven by the current IUIs charge compensated and is driven by a current IDIt is subjected to charge release. I isUControlled by transmission gate TGa, IDControlled by the transmission gate TGb. When the TG gate voltage is switched from low level to high level, Vcp and Vout generate voltage drop, at the moment, the transmission gate TGb is cut off, TGa is conducted, and IUCharge compensation is performed on node mod 1; when Vout recovers the initial voltage level and maintains for a period of time, the gate voltage of TG is switched from high voltage to low voltage, TG is turned off, transmission gate TGa is turned off, transmission gate TGb is turned on, and IDDischarging C1 and C2 to prepare for the voltage drop of Vout in the next period;
FIG. 3 shows a control signal V for a transmission tube TGTGnAnd VTGComparator output signal Vref_outnAnd Vref_outAnd timing diagrams of the transmission gate control signals Va and Vb. VTGGoes high at time t1, VTGnChange to low powerFlat, CloadAnd CoutThe voltage drop of Vout will occur due to charge redistribution, the LDO circuit will start to regulate Vout, it needs to pump charge from the voltage-doubling charge pump, but the charge cannot be transferred instantaneously, so VCPA brief overshoot is generated, at which time the output voltage V of the comparatorref_outnGoes low and masks the clock input to stabilize VCPDuring this period Vref_outIs high level, and VTGPerforming a logical AND operation to generate signals Va, Va being high and Van being low, so that control IUThe transfer gate TGa is turned on to charge the C1 and C2, thereby accelerating the recovery of Vout. At the same time, due to Vref_outnLow, Vb is low, Vbn is high, and transmission gate TGb is off. Vout reverts to a stable initial level at time t2, at which point Vref_outChange to low level, Vref_outnHigh, Va switches from high to low, TGa is off, IUAnd (6) cutting off. Due to VTGnIs low, so Vb is still low, Vbn is high, IDAnd the transistor is still cut off by the transmission gate, so that the stability of the Vout in the turn-on stage of the pixel transmission transistor TG is ensured. time t3, VTGOff, VTGnGoes high, VTGGoes low when Va goes low, resulting in IUAnd (6) cutting off. The LDO circuit does not need to draw charge, V, from the SC CP at this timeCPWill enter a self-adaptive adjustment phase, Vref_outnIs no longer VTGnA mask, Vb and Vbn are intermittently switched between low and high levels, and Vref_outnWhen the transmission gate TGb is opened intermittently, the filter capacitors C1 and C2 pass through IDThe discharge is gradually completed before the next row selection period begins, and the process ensures that the Vout is stable in the discharge process.
As shown in fig. 4, the SC CP charge pump may adopt the circuit structure, which includes switches Switch1, Switch2, Switch3 and Switch4, and the control signals of the four switches are clk, clkn and clk respectively; pump capacitor CpumpAnd output filter capacitor CCP_outWherein the charge pump outputs a filter capacitor CCP_outThe capacitor C1 is connected with the capacitor C2 in series. Switch1 is connected to Switch2 at one end,are connected in series C at the same timepumpThe other end of the Switch1 is connected with the other end of the Switch, which is connected with the Switch 3. The node connecting Switch1 and Switch3 receives the input voltage VIN. The other end of Switch2 is connected in series CCP_outThen connected with one end of Switch4, and the other end of Switch4 is connected with CpumpThe node connected to Switch 2. Switch2 and CCP_outThe connection node of (a) outputs a voltage Vcp. VIN is the SC CP input voltage, clk is from Vref_outnIs AND-operated with the master clock Clk, and can dynamically adjust VCPSo that it is not too high to stabilize the circuit. CpumpThe pump capacitance is generally not more than 1 pf. Due to the presence of the adaptive charge compensation circuit, CCP_outA small capacitor, namely C1 and C2 are connected in series by taking 20pf at the same time, can achieve the expected effect. The clk frequency is usually a clock signal of tens of megabits, and two groups of switches C, which are Switch1, Switch4, Switch2 and Switch3, are controlled to be turned on alternatelypumpAnd (6) charging.
As shown in fig. 5, the LDO circuit includes an error amplifier EA, shunt resistors R3 and R4, and a power transistor Mp. The source end of the power tube Mp is connected with Vcp, the drain end is connected with R3 and R4 in series and then grounded, and the voltage of the connection node of R3 and the Mp drain is the output voltage Vout. Vout is divided by the resistors R3 and R4 to return the voltage of the connection node of the two resistors to the positive end of the operational amplifier, and the negative end of the operational amplifier is connected with a preset reference voltage Vref_LDOThe output end of the operational amplifier is connected with MPThe gate, through a negative feedback mechanism, changes the current flowing through R3 and R4, clamping the Vout voltage to the desired voltage value.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A charge pump with adaptive charge compensation applied to an image sensor is characterized by comprising a switched capacitor charge pump SC CP, a low-dropout linear voltage regulator (LDO) and an adaptive charge compensation circuit, wherein the SC CP is a voltage-multiplying charge pump, an output filter capacitor is in a structure that capacitors C1 and C2 are connected in series, a series node is mod1, and the output voltage Vcp of the SC CPThe LDO is connected to a load circuit after being subjected to voltage stabilization treatment, and the output end of the LDO is connected with an output capacitor Cout，CoutThe other end is grounded, the output voltage is Vout, and the Vout provides a gate bias voltage for all the TGs in a row of pixels in the pixel array at the same time, so that the load capacitance Cload of the charge pump is the sum of the gate parasitic capacitances of all the TGs in the row of pixels; when the gate voltage of TG is switched from low level to high level, TG is conducted, and load capacitor CloadAnd output capacitor CoutAnd the self-adaptive charge compensation circuit dynamically adjusts the SC CP according to the state of the output voltage of the SC CP so as to restore the output voltage to a rated value.
2. The charge pump with adaptive charge compensation as claimed in claim 1, wherein the adaptive charge compensation circuit comprises shunt resistors R1, R2, a comparator Cmp, And gates an 1, an 2, an 3, inverters inv1, inv2, transfer gates TGa And TGb; the output voltage Vcp of the SC CP is grounded through serially connected resistors R1 and R2, meanwhile, the Vcp is connected to the LDO through another branch, a node mod2 connected with the resistors R1 and R2 is connected with one input end of the comparator cmp, and the other input end of the comparator cmp is connected with a signal VrefAn output signal V of the comparator Cmpref_outnThe And master clock signal Clk is anded with the And gate And1 to generate Clk which clocks the SC CP, And two output signals V of the comparator Cmpref_outAnd Vref_outnRespectively AND with VTG And VTGn through AND gates And2 And And3 to generate signals Va And Vb, which are respectively connected to inverters inv1 And inv2 to generate signals Van And Vbn, wherein Va And Van are control signals of a transmission gate TGa, Vb And Vbn are control signals of TGb, And TGa is responsible for controlling a current IUTGb is responsible for controlling the current IDTGa is connected in series with TGb, and the other end of TGa generates IUIs connected to the output of SC CP, and the other end of TGb is connected to generate IDThe current source is grounded again, a serial node of the TGa and the TGb is connected with a mod1 node, and the self-adaptive charge compensation circuit dynamically adjusts the SC CP according to the state of the output voltage Vcp of the SC CP, so that the clock signal of the SC CP is modulated on one hand, and the output voltage of the SC CP is stabilizedThe circuit is prevented from being unstable due to overhigh voltage; on the other hand, when Vcp and Vout are due to CloadAnd CoutWhen voltage drop is generated by charge exchange, the charge is compensated for an output filter capacitor of the SC CP, namely for C1 and C2, so that the transient performance reduction of the LDO caused by Vcp undershoot is prevented; the charge compensation node is mod1, the node is driven by the current IUIs charge compensated and is driven by a current IDPerforming charge release on the glass; i isUControlled by transmission gate TGa, IDControlled by a transmission gate TGb, when the TG gate voltage is switched from low level to high level, Vcp and Vout generate voltage drop, at the moment, the transmission gate TGb is cut off, TGa is conducted, IUCharge compensation is performed on node mod 1; when Vout recovers the initial voltage level and maintains for a period of time, the gate voltage of TG is switched from high voltage to low voltage, TG is turned off, transmission gate TGa is turned off, transmission gate TGb is turned on, and IDDischarge C1, C2 in preparation for the Vout drop for the next cycle.
3. The charge pump with adaptive charge compensation for an image sensor as set forth in claim 1, wherein the control signal V for transmission transistor TGTGComparator output signal Vref_outnAnd Vref_outThe timing of the transmission gate control signals Va and Vb is as follows: vTGGoes high at time t1, VTGnGoes to low level, CloadAnd CoutThe voltage drop of Vout will occur due to charge redistribution, the LDO circuit will start to regulate Vout, it needs to pump charge from the voltage-doubling charge pump, but the charge cannot be transferred instantaneously, so VCPA brief overshoot is generated, at which time the output voltage V of the comparatorref_outnGoes low and masks the clock input to stabilize VCPDuring this period Vref_out is high, and VTGPerforming a logical AND operation to generate signals Va, Va being high and Van being low, so that control IUThe transfer gate TGa is turned on to charge C1 and C2, thereby accelerating the recovery of Vout at the same time due to Vref_outnLow, Vb is low, Vbn is high, transmission gate TGb is turned off, and Vout is restored to the stable initial level at time t2, at which time Vref_outIt is changed to a low level and,Vref_outnva is high, Va is switched from high to low, but V is lowTGnIs low, so Vb is still low, Vbn is high, IDIs still cut off by the transmission gate, so that the stability of Vout in the on-phase of the pixel transmission tube TG at the time t3TGOff, VTGnGoes high, VTGGoes low when Va goes low, resulting in IUOff, when the LDO circuit does not need to draw charge, V, from the SC CPCPWill enter a self-adaptive adjustment phase, Vref_outnIs no longer VTGnA mask, Vb and Vbn are intermittently switched between low and high levels, and Vref_outnWhen the transmission gate TGb is opened intermittently, the filter capacitors C1 and C2 pass through IDThe discharge is gradually completed before the next row selection period begins, and the process ensures that the Vout is stable in the discharge process.
4. The charge pump with adaptive charge compensation as claimed in claim 1, wherein the SC CP charge pump can adopt the following circuit structures, i.e. switches Switch1, Switch2, Switch3 and Switch4, and the control signals of the four switches are clk, clkn and clk; pump capacitor Cpump and output filter capacitor CCP_outWherein the charge pump outputs a filter capacitor CCP_outThe input voltage is SC CP, and the input voltage is VIN formed by connecting capacitors C1 and C2 in series.
5. The charge pump with adaptive charge compensation as claimed in claim 1, wherein the LDO circuit structure comprises an error amplifier EA, shunt resistors R3 and R4, and a power transistor Mp, the power transistor Mp is connected to Vcp at its source terminal, the drain terminal is connected to R3 and R4 in series and then grounded, and the voltage at the node connecting R3 and Mp drain terminal is the output voltage Vout, Vout divides the voltage of the two resistor nodes back to the positive terminal of the operational amplifier by resistors R3 and R4, and the negative terminal of the operational amplifier is connected to a preset reference voltage Vref_LDOThe output end of the operational amplifier is connected with MPA gate for clamping Vout voltage to desired value by changing current flowing through R3 and R4 via negative feedback mechanismThe voltage value of (2).
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| CN113746325B (en) | 2024-02-06 |
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