WO2012132439A1 - 制御信号生成回路、チャージポンプ駆動回路、クロックドライバ、チャージポンプの駆動方法 - Google Patents
制御信号生成回路、チャージポンプ駆動回路、クロックドライバ、チャージポンプの駆動方法 Download PDFInfo
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- WO2012132439A1 WO2012132439A1 PCT/JP2012/002165 JP2012002165W WO2012132439A1 WO 2012132439 A1 WO2012132439 A1 WO 2012132439A1 JP 2012002165 W JP2012002165 W JP 2012002165W WO 2012132439 A1 WO2012132439 A1 WO 2012132439A1
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- control signal
- switch
- generation circuit
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—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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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/16—Modifications for eliminating interference voltages or currents
- H03K17/161—Modifications for eliminating interference voltages or currents in field-effect transistor switches
- H03K17/162—Modifications for eliminating interference voltages or currents in field-effect transistor switches without feedback from the output circuit to the control circuit
- H03K17/163—Soft switching
Definitions
- the present invention relates to a control signal generation circuit, a charge pump drive circuit, a clock driver, and a charge pump drive method that can suppress switching noise.
- switching noise is generated when a steep on / off current IDS (hereinafter referred to as switching current) flows due to a switching operation through a capacitor charged and discharged in the charge pump circuit.
- the magnitude of the switching noise is proportional to the amount of change in the switching current IDS, that is, dIDS / dt obtained by differentiating the switching current IDS with respect to time.
- FIG. 11 is a diagram showing a conventional charge pump drive circuit that prevents a steep switching current IDS from flowing through a capacitor during a switching operation.
- the illustrated driving circuit includes a step-down charge pump circuit having a capacitor Cf for storing and transporting charges, a capacitor Co for storing charges transported from the capacitor Cf, and MOS transistors 1 to 4, a MOS transistor 1
- the charge pump (CP) control circuit 5 controls the gate voltages of .about.4.
- the CP control circuit 5 includes a clock signal generation circuit 6 that generates a clock and a resistance element 7 for blunting the rising waveform and falling waveform of the clock.
- a control circuit for such a charge pump circuit is described in, for example, Patent Document 1.
- the CP control circuit 5 shown in FIG. 11 inserts a resistance element 7 into the gate input node of the MOS transistor that charges and discharges the capacitors Cf and Co, so that the rising slew rate of the gate voltage VG of the MOS transistors 1 to 4 or Reduce the falling slew rate.
- the reduction of the slew rate can moderate the on / off of the switches of the MOS transistors 1 to 4 and suppress the steep switching current IDS flowing through the capacitors Cf and Co.
- FIGS. 12A to 12D are all waveforms of clock signals input to the MOS transistor at the uppermost stage, and are waveforms before passing through the resistance element 7 and waveforms after passing through the resistance element 7. Is shown. In the next stage, the waveform of the gate voltage VG (the waveform after passing through the resistance element 7) is shown. The waveform of the switching current IDS flowing between the source and drain of the MOS transistor is shown in the next stage, and the time differential waveform of the switching current IDS is shown in the bottom stage.
- FIG. 12A shows the above waveform when the N-type MOS transistor is on
- FIG. 12B shows the above waveform when the N-type MOS transistor is off
- FIG. 12C shows the waveform when the P-type MOS transistor is on
- FIG. 12D shows the waveform when the P-type MOS transistor is off.
- the threshold voltage Vth is a threshold voltage of the MOS transistor.
- the PMOS transistor is similarly turned on by the clock signal
- the NMOS transistor is similarly turned on and off by the clock signal.
- the clock signal after passing through the resistance element 7, that is, the gate voltage becomes gentle, and accordingly, the time change of the switching current IDS becomes gentle.
- the differential value dIDS / dt is suppressed in the vicinity of the threshold value at which the MOS transistor is turned on and off, and the switching noise is reduced.
- the present invention has been made in view of the above points, and is a control signal generation circuit, a charge pump drive circuit, a clock driver, and a drive of a charge pump that generate a control signal that can further suppress switching current and reduce switching noise. It aims to provide a method.
- a control signal generation circuit of one embodiment of the present invention includes a control signal generation circuit that generates a control signal for controlling the gate of a MOS transistor (for example, FIG. 1, FIG. 2, FIG. 4,
- the control signal generation circuit 107 shown in FIGS. 6 and 8 is connected to a current source (for example, a constant current source 205) and a gate, and is controlled based on an input signal (for example, Vin shown in FIG. 2).
- the first switch unit for example, the switch 202 shown in FIG. 2), the current source (for example, the constant current source 204 shown in FIG. 2), and the gate are connected to the input signal and the control signal (for example, V shown in FIG. 2).
- a second switch unit (for example, the switches 201 and 203 shown in FIG. 2) controlled based on the control signal, the voltage value of the control signal transits based on the input signal, and the slope of the voltage value with respect to time Is the voltage value
- the voltage value is switched to be smaller after exceeding the threshold voltage of the MOS transistor than when the voltage is less than or equal to the threshold voltage of the MOS transistor.
- the change in the switching current of the MOS transistor can be moderated before and after the timing at which the threshold voltage is applied to the MOS transistor in the charge pump circuit. For this reason, the switching noise of the charge pump circuit can be reduced.
- the first switch unit includes a first switch (for example, the switch 202 illustrated in FIG. 2) that is on / off controlled by an input signal.
- the switch unit includes a second switch (for example, the switch 201 illustrated in FIG. 2) that is ON / OFF controlled by an input signal, and an output control unit (for example, the switch illustrated in FIG. 2) that controls the current flowing through the second switch based on the control signal. 203, 206).
- the current source (for example, the constant current sources 204 and 205 illustrated in FIG. 2) has a current value equal to that of the first switch and the second switch. May be supplied.
- the current source includes a first current source (for example, the constant current source 205 illustrated in FIG. 2) that supplies current to the first switch,
- the second switch may include a second current source (for example, the constant current source 204 shown in FIG. 2) that supplies a current having a value different from that of the current supplied by the first current source.
- the output control unit compares the voltage value of the control signal with the threshold value of the MOS transistor (for example, the comparator 206 illustrated in FIG. 2). And a third switch (for example, the switch 203 shown in FIG. 2) that is on / off controlled based on the comparison result of the comparator.
- the third switch may stop current from flowing through the second switch when the MOS transistor is turned off from the on state. Also good.
- the third switch supplies the current stopped when the MOS transistor is turned on from the off state to the second switch. You may make it flow.
- the output control unit may include a diode (for example, the switch 1003 illustrated in FIG. 10).
- the control signal generation circuit of one embodiment of the present invention further includes a delay unit (for example, the delay unit 208 illustrated in FIG. 2) that generates a delay signal obtained by delaying the input signal in the above-described invention.
- the unit may enable supply of current to the gate according to the delay signal.
- the control signal generation circuit of one embodiment of the present invention further includes a delay unit (for example, the delay unit 408 illustrated in FIG. 4) that generates a delay signal obtained by delaying the input signal in the above-described invention, and the second switch The unit may enable supply of current to the gate according to the delay signal.
- a charge pump driving circuit of one embodiment of the present invention includes at least one control signal generation circuit (for example, the control signal generation circuit 107 illustrated in FIG. 1) and at least one MOS transistor (for example, illustrated in FIG. 1). And a capacitive element (for example, the capacitor 109 shown in FIG. 1) charged and discharged by the MOS transistor.
- a clock driver of one embodiment of the present invention includes the control signal generation circuit, and drives a MOS transistor provided at a stage subsequent to the control signal generation circuit based on a clock signal output from the control signal generation circuit. It is a characteristic.
- a charge pump driving method is a charge pump driving method for driving a charge pump including at least one MOS transistor and a capacitor element charged and discharged by the MOS transistor.
- a control signal is generated that switches the slope to a smaller value than when the input signal is less than or equal to the threshold value of the MOS transistor, A current is supplied to the gate of the MOS transistor based on the input signal and the control signal.
- control signal generation circuit that can moderate the change in the switching current of the MOS transistor before and after the timing at which the threshold voltage is applied to the MOS transistor in the charge pump circuit and reduce the switching noise of the charge pump circuit,
- a charge pump driving circuit, a clock driver, and a charge pump driving method can be provided.
- FIG. 3 is a diagram for explaining an operation of a control signal generation circuit shown in FIG. 2. It is a figure for demonstrating the structure of the control signal generation circuit which outputs the control signal for PMOS transistor ON of 1st Embodiment of this invention.
- FIG. 5 is a diagram for explaining the operation of the control signal generation circuit shown in FIG. 4. It is a figure for demonstrating the structure of the control signal generation circuit which outputs the control signal for NMOS transistor OFF of 1st Embodiment of this invention.
- FIG. 3 is a diagram for explaining an operation of a control signal generation circuit shown in FIG. 2. It is a figure for demonstrating the structure of the control signal generation circuit which outputs the control signal for PMOS transistor ON of 1st Embodiment of this invention.
- FIG. 5 is a diagram for explaining the operation of the control signal generation circuit shown in FIG. 4. It is a figure for demonstrating the structure of the control signal generation circuit which outputs the control signal for NMOS transistor OFF of 1st Embodiment of this
- FIG. 7 is a diagram for explaining an operation of a control signal generation circuit 107 shown in FIG. 6. It is a figure for demonstrating the structure of the control signal generation circuit 107 which outputs the control signal for NMOS transistor ON.
- FIG. 9 is a diagram for describing an operation of a control signal generation circuit 107 illustrated in FIG. 8. It is a figure for demonstrating the structure of the control signal generation circuit of 2nd Embodiment. It is the figure which showed the conventional charge pump drive circuit.
- FIG. 12 is a diagram showing clock signals and the like of MOS transistors 1 to 4 shown in FIG.
- FIG. 1 is a diagram for explaining the charge pump drive circuit according to the first embodiment.
- the charge pump drive circuit according to the first embodiment includes a capacitor 109 for storing and transporting charges, a capacitor 110 for storing charges transported from the capacitor 109, and MOS transistors 101 to 104.
- the pump circuit 108 and the capacitors 109 and 110 are constituted by a charge pump (CP) control circuit 105 that charges and discharges by controlling the gate voltages of the MOS transistors 101 to 104.
- a predetermined voltage is input from the terminal VDD PIN, and a voltage stepped down to a desired value is output from the terminal VEE PIN.
- a PMOS transistor or an NMOS transistor is appropriately selected from the MOS transistors 101 to 104 depending on the voltage level of a signal handled by the charge pump drive circuit.
- the charge pump circuit 108 and the CP control circuit 105 may be integrated as an IC.
- the capacitor 109 may be provided outside the IC via a terminal (CP PIN, CN PIN), and the capacitor 110 may be provided outside the IC via a terminal (VEE PIN, GND PIN).
- the CP control circuit 105 includes a clock signal generation circuit 106 and a control signal generation circuit 107 that changes the rising and falling waveforms of the branched clock signal. According to the CP control circuit 105, the control signal generation circuit 107 can turn on or off the MOS transistors 101 to 104 slowly. Since the MOS transistors 101 to 104 are slowly turned on and off, it is possible to suppress a steep switching current from flowing due to the switching operation, and to reduce switching noise.
- the control signal generation circuit 107 can also be used as a clock driver.
- the clock driver is configured to receive a clock signal and generate a clock signal for driving a MOS transistor in the subsequent stage.
- the clock driver provided with the control signal generation circuit 107 changes the rising and falling waveforms of the clock signal by the control signal generation circuit 107 to turn on or off the MOS transistor later than the control signal generation circuit 107 slowly. Can do.
- the clock driver can suppress a steep switching current from flowing due to the switching operation and reduce the switching noise.
- the control signal generation circuit 107 of the first embodiment can reduce the change amount of the switching current by making the rise and fall of the gate voltage of the MOS transistor near the threshold voltage having the largest current change amount more gradual.
- the control signal generation circuit 107 according to the first embodiment includes a “control signal for turning off the PMOS transistor”, a “control signal for turning on the PMOS transistor”, a “control signal for turning off the NMOS transistor”, and “NMOS It is possible to generate four patterns of control signals “transistor-on control signal”.
- FIG. 2 is a diagram for explaining the configuration of the control signal generating circuit 107 that outputs a control signal for turning off a PMOS transistor.
- the control signal generation circuit 107 is connected to a power supply terminal (not shown) that supplies the power supply voltage VDD (hereinafter simply referred to as the power supply voltage VDD).
- the control signal generation circuit 107 includes constant current sources 204 and 205 that cause a constant current to flow through the node a indicated by the symbol “a” in FIG.
- the constant current sources 204 and 205 can flow the same current.
- the control signal generation circuit 107 includes a comparator 206, three switches 201 to 203 that connect and disconnect the node a and the constant current sources 204 and 205, and a delay unit 208.
- the current supplied from the constant current source 204 and the current supplied from the constant current source 205 are added via the switches 201 to 203.
- the delay unit 208 is a circuit that generates a signal obtained by delaying the input signal Vin.
- Delay unit 208 includes two inverters connected in series and a capacitor connected in parallel to the inverter. Since the switch 202 receives the signal delayed by the delay unit 208, the switch 202 operates later than the switch 201.
- control signal generation circuit 107 includes a switch 207 that connects and disconnects a node a and a terminal of a power supply (not shown) that supplies the power supply voltage VSS (hereinafter simply referred to as a power supply voltage VSS).
- the switch 207 is configured by an NMOS transistor. An input signal Vin is input to the switch 207. Since the switch 207 operates complementarily with the switches 201 and 202, a control signal for turning on the PMOS transistor can be output.
- FIGS. 3A to 3D are diagrams for explaining the operation of the control signal generation circuit 107 shown in FIG.
- FIG. 3A is a graph in which the voltage of the input signal Vin input to the switches 201 and 207 and the delay unit 208 is shown on the vertical axis, and the time t is shown on the horizontal axis.
- FIG. 3B is a graph in which the potential of the node a shown in FIG. 2 is plotted on the vertical axis and the time t is plotted on the horizontal axis. The potential of the node a becomes the voltage VG applied to the gate of the PMOS transistor.
- FIG. 3C is a graph showing the switching current IDS flowing through the PMOS transistor on the vertical axis and the time t on the horizontal axis.
- FIG. 3D is a graph showing the time differential value of the switching current IDS shown in FIG. 3C on the vertical axis and the time t on the horizontal axis.
- the input signal Vin is input to the switches 201 and 207, and controls the switching of the switches 201 and 207.
- the input signal Vin is input to the switch 202 via the delay unit 208, and the delayed signal controls the switching of the switch 202.
- the voltage Vc input to the comparator 206 is a constant voltage (VDD ⁇ Vth). When the potential of the node a becomes close to (VDD ⁇ Vth), the signal output from the comparator 206 is gradually inverted and the switch 203 is gradually turned off.
- the threshold voltage Vth is the threshold voltage of the PMOS transistor shown in FIG. 2 and is the same as the threshold voltage of the PMOS transistor constituting the switch 203.
- the control signal generation circuit 107 When outputting a control signal for turning off the PMOS transistor, the control signal generation circuit 107 operates as follows. That is, as shown in FIG. 3A, when the voltage of the input signal Vin is High (hereinafter, simply referred to as “H”), the switch 207 is in an on state, so that FIG. As shown, the potential of the node a is VSS. Next, when the voltage of the input signal Vin changes from H ⁇ Low (hereinafter simply referred to as “L”) at time t1, the switch 201 is turned on and the switch 207 is turned off. At this time, the switch 203 is on. At this time, the switch 202 is switched off by the signal delayed by the delay unit 208 and thus is in the off state.
- H High
- L Low
- a current flows from the constant current source 204 to the switches 201 and 203, and charges are charged in the gate capacitance of the PMOS transistor shown in FIG. For this reason, the potential of the node a rises with a constant slope until the potential of the node a reaches near VDD ⁇ Vth.
- the change of the switching current IDS is around the time t2 when the PMOS transistor reaches the threshold voltage Vth at which the PMOS transistor is turned off. Becomes smaller. That is, according to the first embodiment, the change in the switching current IDS is suppressed before and after the time t2 when the PMOS transistor reaches the threshold voltage to turn off, and the switching noise is reduced.
- the voltage Vc input to the comparator 206 is (VDD ⁇ Vth).
- Vth may be set to a value close to the threshold voltage of the MOS transistors before and after.
- the constant current sources 204 and 205 are different constant current sources for supplying the same value of current.
- the constant current sources 204 and 205 may be replaced with one constant current source.
- the constant current sources 204 and 205 are constant current sources that supply the same value of current. However, if the constant current source 205 is configured to flow a large value of current, the time t3 to the time t4 are set. Can be shortened. Further, if a constant current source 204 is caused to flow a large value of current, the period from time t1 to time t2 can be shortened.
- the first embodiment is not limited to the above-described configuration.
- the first embodiment may be configured without the delay unit 208 shown in FIG.
- the switches 201, 202, and 203 are turned on from time t1 to time t2 shown in FIG.
- a current obtained by adding the current supplied from the constant current source 204 and the current supplied from the constant current source 205 flows to the node a.
- the potential of the node a rises with a constant slope while a current obtained by adding the current supplied by the constant current source 204 and the current supplied by the constant current source 205 flows to the node a.
- the switch 203 is turned off.
- the potential of the node a is obtained by adding the current supplied by the constant current source 204 and the current supplied by the constant current source 205.
- the current rises at a gentler slope than when the current flows through node a, and reaches VDD.
- the change in the gate voltage VG near VDD-Vth at time t2 becomes gradual and the switching noise is reduced, similarly to the control signal generation circuit 107 shown in FIG. can do.
- FIG. 4 is a diagram for explaining a configuration of the control signal generation circuit 107 that outputs a PMOS transistor ON control signal.
- the control signal generation circuit 107 includes a constant current source 405 that is connected to the power supply voltage VDD and supplies a constant current to the node, and a constant current source 404 that is connected to the power supply voltage VSS and supplies a constant current to the node. ing.
- the constant current sources 404 and 405 are constant current sources that supply the same value of current.
- control signal generation circuit 107 includes a comparator 406, a node b indicated by a symbol “b” in FIG. 4, three switches 401 to 403 that connect and disconnect the constant current sources 404 and 405, and a delay. Part 408.
- the switches 401 and 402 are composed of PMOS transistors, and the switch 403 is composed of NMOS transistors.
- Node b is a node for applying a voltage signal to the gate of the PMOS transistor shown in FIG.
- the delay unit 408 is a circuit that generates a signal obtained by delaying the input signal Vin.
- Delay unit 408 includes two inverters connected in series and a capacitor connected in parallel to the inverter. Since the signal delayed by the delay unit 408 is input to the switch 401, the switch 401 operates later than the switch 403.
- the control signal generation circuit 107 includes a switch 407 that connects and disconnects the node b and the power supply voltage VDD.
- the switch 407 is configured by a PMOS transistor. Since the input signal Vin is input to the switch 407 and operates complementarily to the switch 403, a control signal for turning off the PMOS transistor can be output.
- FIGS. 5A to 5D are diagrams for explaining the operation of the control signal generation circuit 107 shown in FIG.
- FIG. 5A is a graph in which the voltage Vin of the input signal input to the switches 403 and 407 and the delay unit 408 is shown on the vertical axis, and the time t is shown on the horizontal axis.
- FIG. 5B is a graph showing the potential of the node b shown in FIG. 4 on the vertical axis and the time t on the horizontal axis.
- FIG. 5C is a graph showing the switching current IDS flowing through the PMOS transistor on the vertical axis and the time t on the horizontal axis.
- FIG. 5D is a graph showing the time differential value of the switching current IDS shown in FIG. 5C on the vertical axis and the time t on the horizontal axis.
- the input voltage Vin is input to the switches 403 and 407, and the switching of the switches 403 and 407 is controlled.
- the input signal Vin is input to the switch 401 via the delay unit 408.
- the signal delayed by the delay unit 408 controls the switching of the switch 401.
- Vc is a constant voltage (VDD-Vth). When the potential of the node b becomes Vc or less, the signal output from the comparator 406 is inverted and the switch 402 is turned on.
- the threshold voltage Vth is the threshold voltage of the PMOS transistor shown in FIG. 4 and is the same as the threshold voltage of the PMOS transistor constituting the switch 402.
- the control signal generation circuit 107 When outputting a control signal for turning on the PMOS transistor, the control signal generation circuit 107 operates as follows. That is, as shown in FIG. 5A, when the voltage of the input signal Vin is L, the switch 407 is in an on state. For this reason, as shown in FIG. 5B, the potential of the node b becomes VDD.
- the switch 403 is turned on and the switch 407 is turned off. At this time, the switch 402 is off. Further, the switch 401 is in an ON state because it is switched by the signal delayed by the delay unit 408. As shown in FIG. 5B, a current flows from the constant current source 404 to the switch 403, and the charge of the gate capacitance of the PMOS transistor is discharged. For this reason, during the time t1 to t2, the potential of the node b falls with a certain slope.
- the switch 402 is turned on by the inversion of the output signal.
- the switch 403 receives a current from the constant current source 404, and the switches 401, 402 receive a current having the same value as the current flowing from the constant current source 404. It flows from the constant current source 405. For this reason, as shown in FIG. 5B, the potential of the node b is maintained at (VDD ⁇ Vth), and the inclination becomes substantially zero.
- the voltage Vc input to the comparator 406 is (VDD ⁇ Vth).
- the voltage Vc may be set near the threshold value of the MOS transistor around (VDD-Vth).
- the first embodiment is not limited to the configuration described above, and may be configured without the delay unit 408 shown in FIG. 4, for example.
- the constant current source 404 supplies a current having a value larger than that of the constant current source 405, and the switch 401 is controlled by a signal whose phase is opposite to that of the input signal Vin.
- the switch 403 is turned on and current is supplied from the constant current source 404, so the potential of the node b drops with a predetermined slope.
- the switch 402 is turned on, and a current smaller than the current of the constant current source 404 further flows from the constant current source 405.
- the potential gradient of the node b drops with a gentler slope than the gradient when the current flows from the constant current source 404 to the node b, and reaches VSS.
- the control signal generation circuit without the delay unit 408 moderates the change in the gate voltage VG near VDD-Vth at time t2 and reduces the switching noise, similarly to the control signal generation circuit 107 shown in FIG. can do.
- FIG. 6 is a diagram for explaining the configuration of the control signal generating circuit 107 that outputs the control signal for turning off the NMOS transistor.
- the control signal generation circuit 107 includes constant current sources 604 and 605 that are connected to the power supply voltage VSS and cause a constant current to flow through the nodes.
- the constant current sources 604 and 605 can pass the same current.
- the control signal generation circuit 107 includes a comparator 606, three switches 601 to 603 that connect and disconnect the constant current sources 604 and 605 with the node c denoted by “c” in FIG. 6, a delay unit 608, Is included.
- the switches 601 to 603 are constituted by NMOS transistors.
- the delay unit 608 is a circuit that generates a signal obtained by delaying the input signal Vin.
- Delay unit 608 includes two inverters connected in series and a capacitor connected in parallel to the inverter. Since the signal delayed by the delay unit 608 is input to the switch 602, the switch 602 operates later than the switch 601.
- the control signal generation circuit 107 includes a switch 607 that connects and disconnects the node c and the power supply voltage VDD.
- the switch 607 is configured by a PMOS transistor. Since the input signal Vin is input to the switch 607 and operates complementarily to the switches 601, 602, a control signal for turning on the NMOS transistor can be output.
- FIGS. 7A to 7D are diagrams for explaining the operation of the control signal generation circuit 107 shown in FIG.
- FIG. 7A is a graph in which the vertical axis indicates the voltage of the input signal Vin input to the switches 601 and 607, and the horizontal axis indicates time t.
- FIG. 7B is a graph showing the potential of the node c shown in FIG. 6 on the vertical axis and the time t on the horizontal axis. The potential of the node c becomes the voltage VG applied to the gate of the NMOS transistor.
- FIG. 7C is a graph showing the switching current IDS flowing through the NMOS transistor on the vertical axis and the time t on the horizontal axis.
- FIG. 7D is a graph showing the time differential value of the switching current IDS shown in FIG. 7C on the vertical axis and the time t on the horizontal axis.
- the input signal Vin is input to the switches 601 and 607, and the switching of the switches 601 and 607 is controlled.
- the input signal Vin is input to the switch 601 via the delay unit 608.
- the signal delayed by the delay unit 608 controls the switching of the switch 602.
- Vc inputted to the comparator 606 is a constant threshold voltage Vth, and when the node c becomes near the threshold voltage Vth, the signal outputted from the comparator 606 is gradually inverted, and the switch 603 is gradually turned off.
- the threshold voltage Vth is the threshold voltage of the NMOS transistor shown in FIG. 6 where the node c is connected to the gate, and is the same as the threshold voltage of the NMOS transistor constituting the switch 603.
- the control signal generation circuit 107 When outputting a control signal for turning on the NMOS transistor, the control signal generation circuit 107 operates as follows. That is, as shown in FIG. 7A, when the voltage of the input signal Vin is L, the switch 607 is on. For this reason, as shown in FIG. 7B, the potential of the node c becomes VDD.
- the switch 601 is turned on and the switch 607 is turned off. At this time, the switch 603 is on. At this time, a current flows from the current source 604 to the switches 601 and 603, and charges are discharged from the gate capacitance of the NMOS transistor. As a result, as shown in FIG. 7B, the potential of the node c drops.
- the switch 602 is in an OFF state because it performs a switching operation by the signal delayed by the delay unit 608. For this reason, no current flows into the switch 602 from the constant current source 605.
- Vc Vth
- the signal output from the comparator 606 is gradually inverted, and the switch 603 is gradually turned off. Therefore, as shown in FIG. 7B, the potential at the node c reaches the vicinity of the threshold voltage Vth at time t2, and then enters a floating state, and the gradient becomes substantially zero.
- the change in the switching current IDS of the NMOS transistor becomes small around time t2. That is, according to such a configuration, the value of the switching current IDS is suppressed before and after the time t2 close to the threshold voltage at which the NMOS transistor is turned off, and the switching noise is reduced.
- the voltage Vc input to the comparator 606 is the threshold voltage Vth.
- the voltage Vc is set to the MOS before and after the threshold voltage Vth. What is necessary is just to set to the threshold value vicinity of a transistor.
- the constant current sources 604 and 605 are different constant current sources that supply the same value of current. However, the constant current sources 604 and 605 may be replaced with one constant current source.
- the constant current sources 604 and 605 are constant current sources that supply the same value of current. However, if the constant current source 605 is configured to flow a large value of current, the time t4 is changed to the time t4. Can be shortened. Further, if a constant current source 604 is caused to flow a large current, the period from time t1 to time t2 can be shortened.
- the first embodiment is not limited to the configuration described above, and may be configured without the delay unit 608 shown in FIG. 6, for example.
- the switches 601, 602, and 603 are turned on from time t1 to time t2.
- a current obtained by adding the currents of the constant current sources 604 and 605 flows through the node c.
- the potential of the node c drops at a constant slope while a current obtained by adding the currents of the constant current sources 604 and 605 flows to the node c.
- the switch 603 is gradually turned off, and then only the current from the current source 605 flows to the node c.
- the potential of the node c drops with a gentler slope than when the current obtained by adding the currents of the constant current sources 604 and 605 flows to the node c, and reaches VSS.
- the control signal generation circuit 107 without the delay circuit 608 moderates the change in the gate voltage VG in the vicinity of VDD ⁇ Vth at time t 2 and reduces switching noise. can do.
- FIG. 8 is a diagram for explaining a configuration of a control signal generating circuit 107 that outputs a control signal for turning on an NMOS transistor.
- the control signal generation circuit 107 includes a constant current source 804 that is connected to the power supply voltage VDD and supplies a constant current to the node, and a constant current source 805 that is connected to the power supply voltage VSS and supplies a constant current to the node. ing.
- the constant current sources 804 and 805 are constant current sources that supply the same value of current.
- control signal generation circuit 107 includes a comparator 806, three switches 801 to 803 that connect and disconnect the node d denoted by “d” in FIG. 8 and the constant current sources 804 and 805, and a delay unit 808. , Including.
- the switches 801 and 802 are NMOS transistors, and the switch 803 is a PMOS transistor.
- Node d is a node for applying a voltage signal to the gate of the NMOS transistor shown in FIG.
- the delay unit 808 is a circuit that generates a signal obtained by delaying the input signal Vin.
- Delay unit 808 includes two inverters connected in series and a capacitor connected in parallel to the inverter. Since the signal delayed by the delay unit 808 is input to the switch 801, the switch 801 operates later than the switch 803.
- the control signal generation circuit 107 includes a switch 807 that connects and disconnects the node d and the power supply voltage VSS.
- the switch 807 is configured by an NMOS transistor. Since the input voltage Vin is input to the switch 807 and operates complementarily to the switch 803, a control signal for turning off the NMOS transistor can be output.
- FIGS. 9A to 9D are diagrams for explaining the operation of the control signal generation circuit 107 shown in FIG.
- FIG. 9A is a graph showing the input voltage Vin input to the switches 803 and 807 and the delay unit 808 on the vertical axis and the time t on the horizontal axis.
- FIG. 9B is a graph showing the potential of the node d shown in FIG. 8 on the vertical axis and the time t on the horizontal axis.
- FIG. 9C is a graph showing the switching current IDS flowing through the NMOS transistor on the vertical axis and the time t on the horizontal axis.
- FIG. 9D is a graph showing the time differential value of the switching current IDS shown in FIG. 9C on the vertical axis and the time t on the horizontal axis.
- the input voltage Vin is input to the switches 803 and 807, and the switching of the switches 803 and 807 is controlled.
- the input signal Vin is input to the switch 801 via the delay unit 808, and the signal delayed by the delay unit 808 controls the switching of the switch 801.
- Vc is a constant threshold voltage Vth, and when the potential of the node d becomes Vc or less, the signal output from the comparator 806 is inverted and the switch 802 is turned on.
- the threshold voltage Vth is the threshold voltage of the NMOS transistor shown in FIG.
- the control signal generation circuit 107 When outputting a control signal for turning on the NMOS transistor, the control signal generation circuit 107 operates as follows. That is, as shown in FIG. 9A, when the input voltage Vin is H, the switch 807 is in the ON state, so that the potential of the node d is VSS as shown in FIG. It becomes. Next, when the input voltage Vin changes from H to L at time t1, the switch 803 is turned on and the switch 807 is turned off. At this time, the switch 802 is off. In addition, the switch 801 is switched on by the signal delayed by the delay unit 808, and thus is on. As shown in FIG. 5B, a current flows from the constant current source 804 to the switch 803. At this time, since the charge is charged in the gate capacitance of the NMOS transistor, the potential of the node d rises with a certain slope during the time t1 to t2.
- the signal output from the comparator 806 is inverted and the switch 802 is turned on.
- the current supplied from the constant current source 804 flows through the switch 803 during the time t2 to t3 when the switch 801 and the switch 803 are on.
- a current having the same value as the current supplied from the constant current source 804 flows from the constant current source 805 to the switches 801 and 802. For this reason, as shown in FIG. 9B, the potential of the node d is maintained at the threshold voltage Vth, and the gradient becomes substantially zero.
- the voltage Vc input to the comparator 806 is the threshold voltage Vth.
- the voltage Vc is set to the MOS before and after the threshold voltage Vth. What is necessary is just to set to the threshold value vicinity of a transistor.
- the first embodiment is not limited to the configuration described above, and may be configured without the delay unit 808 shown in FIG. 8, for example.
- the constant current source 804 is caused to flow a current having a value larger than that of the constant current source 805, and the switch 801 is controlled by a signal whose phase is opposite to that of the input signal Vin.
- the switch 803 is turned on from time t1 to time t2, and the current supplied from the constant current source 804 flows through the node d. While the current supplied from the constant current source 804 flows to the node d, the potential of the node d rises with a constant slope. At time t2, the switch 802 is turned on, and a current smaller than the current of the constant current source 804 is supplied from the constant current source 805 to the node d. For this reason, the potential of the node d rises with a gentler slope than when the current supplied from the constant current source 804 flows to the node d and reaches VDD. As a result, similarly to the control signal generation circuit 107 shown in FIG. 8, the control signal generation circuit 107 without the delay circuit 808 moderates the change in the gate voltage VG near the threshold voltage Vth at time t2 and reduces switching noise. can do.
- FIG. 10 is a diagram for explaining the control signal generation circuit 1007 of the second embodiment.
- the second embodiment is different from the first embodiment in that the PMOS transistor shown in FIG. 10 is controlled by a diode-connected switch.
- FIG. 10 shows an example in which the control signal generation circuit 1007 outputs a control signal for turning off the PMOS transistor.
- the control signal generation circuit 1007 shown in FIG. 10 has a switch 1003 instead of the switch 203 and the comparator 206 shown in FIG.
- Such a control signal generation circuit 1007 includes four switches 1001 to 1003 and 1006, a constant current source 1004, a constant current source 1005, and a delay unit 1008.
- the switches 1001 to 1003 are composed of PMOS transistors, and the switch 1006 is composed of NMOS transistors.
- the switch 1003 is composed of a PMOS transistor.
- the gate and drain are commonly connected and diode-connected.
- the input voltage Vin is input to the switches 1001 and 1002 and the switch 1004.
- the gate voltage VG of the PMOS transistor shown in FIG. 10 is close to VDD-Vth
- VG of the switch 1003 is close to the threshold voltage
- the switch 1003 is gradually turned off.
- the same operation as that of the control signal generation circuit 107 of the first embodiment shown in FIG. 3 can be performed.
- the second embodiment a case where a control signal for turning off the PMOS transistor is output is taken as an example.
- the second embodiment includes a control signal generation circuit that can generate any of the control signal for turning on the PMOS transistor, the control signal for turning off the NMOS transistor, and the control signal for turning on the NMOS transistor. It can be configured using a diode.
- the present invention can be applied to all circuits that generate a control signal for driving a charge pump.
- Control signal generation circuit 109 110 Capacitor 101 to 104 MOS transistors 201 to 203, 207, 401 to 403, 407, 601 to 603, 607, 801 to 803, 807, 1001 to 1003 , 1006, 1007, 1010 Switch 204, 205, 404, 405, 604, 605, 804, 805, 1004, 1005, 1009 Constant current source 206, 406, 606, 806 Comparator 208, 408, 608, 808 Delay unit
Abstract
Description
スイッチングノイズの大きさは、スイッチング電流IDSの変化量、つまり、スイッチング電流IDSを時間で微分した、dIDS/dtに比例する。
図示した駆動回路は、電荷を蓄積、搬送するコンデンサCfと、コンデンサCfから搬送されてきた電荷を蓄積するコンデンサCoと、MOSトランジスタ1~4と、を有する降圧式チャージポンプ回路と、MOSトランジスタ1~4のゲート電圧を制御するチャージポンプ(CP)制御回路5によって構成されている。
CP制御回路5は、クロックを生成するクロック信号生成回路6と、それらクロックの立ち上がり波形及び立ち下がり波形を鈍らせるための抵抗素子7とを含んでいる。なお、このようなチャージポンプ回路の制御回路は、例えば、特許文献1に記載されている。
例えば、図12(d)のように、PMOSトランジスタがオフする場合を考える。このとき、クロック信号がL→Hになると、抵抗素子7を通過した後のクロック信号、すなわちゲート電圧VGは、緩やかに上昇する。それに伴い、スイッチング電流IDSが緩やかに降下する。ゲート電圧VGがVDD-Vthまで上昇すると、PMOSトランジスタがオフする。ここで、閾値電圧Vthは、MOSトランジスタの閾値電圧である。
このようなチャージポンプ駆動回路によれば、抵抗素子7を通過した後のクロック信号、すなわちゲート電圧が緩やかになり、それに伴い、スイッチング電流IDSの時間変化が緩やかになるため、スイッチング電流IDSの時間微分値dIDS/dtが、MOSトランジスタがオン、オフする閾値付近で抑制されてスイッチングノイズが低減される。
図11に示したチャージポンプ駆動回路では、NMOSトランジスタ、PMOSトランジスタ共に、オフ時のゲート電圧の変化が小さいため電流変化量が抑えられ、スイッチングノイズを小さくすることができる。
本発明は、上記した点に鑑みてなされたものであり、スイッチング電流をさらに抑制し、スイッチングノイズを低減できる制御信号を生成する制御信号生成回路、チャージポンプ駆動回路、クロックドライバ、チャージポンプの駆動方法を提供することを目的とする。
また、本発明の一態様の制御信号生成回路は、上記した発明において、第1スイッチ部が、入力信号によりオンオフ制御される第1スイッチ(例えば図2に示したスイッチ202)を備え、第2スイッチ部は、入力信号によりオンオフ制御される第2スイッチ(例えば図2に示したスイッチ201)と、制御信号に基づき第2スイッチに流れる電流を制御する出力制御部(例えば図2に示したスイッチ203、206)と、を備えるようにしてもよい。
また、本発明の一態様の制御信号生成回路は、上記した発明において、電流源が、第1スイッチに電流を供給する第1電流源(例えば図2に示した定電流源205)と、前記第2スイッチに、前記第1電流源によって供給される電流と値が異なる電流を供給する第2電流源(例えば図2に示した定電流源204)と、を備えるようにしてもよい。
また、本発明の一態様の制御信号生成回路は、上記した発明において、第3スイッチが、MOSトランジスタがオン状態からオフ状態になったとき、第2スイッチに電流が流れることを止めるようにしてもよい。
また、本発明の一態様の制御信号生成回路は、上記した発明において、出力制御部は、ダイオード(例えば図10に示したスイッチ1003)を備えるようにしてもよい。
また、本発明の一態様の制御信号生成回路は、上記した発明において、入力信号を遅延させた遅延信号を生成する遅延部(例えば図4に示した遅延部408)をさらに備え、第2スイッチ部は、遅延信号に従いゲートに電流を供給可能とするようにしてもよい。
[第1実施形態]
[チャージポンプ駆動回路]
図1は、第1実施形態のチャージポンプ駆動回路を説明するための図である。第1実施形態のチャージポンプ駆動回路は、電荷を蓄積、搬送するコンデンサ109と、コンデンサ109から搬送されてきた電荷を蓄積するコンデンサ110と、MOSトランジスタ101~104と、を備えた降圧式のチャージポンプ回路108と、コンデンサ109、110をMOSトランジスタ101~104のゲート電圧を制御することによって充放電するチャージポンプ(CP)制御回路105と、によって構成される。そして、端子VDD PINから所定の電圧を入力し、端子VEE PINより所望の値に降圧した電圧を出力している。
CP制御回路105によれば、制御信号生成回路107により、MOSトランジスタ101~104をゆっくりとオン、またはオフさせることができる。MOSトランジスタ101~104がゆっくりオン、オフすることにより、スイッチング動作によって急峻なスイッチング電流が流れるのを抑制し、スイッチングノイズを減らすことができる。
また、制御信号生成回路107は、クロックドライバにも利用できる。なお、ここで、クロックドライバとは、クロック信号が入力され、後段のMOSトランジスタを駆動するためのクロック信号を生成する構成とする。
制御信号生成回路107を備えたクロックドライバは、制御信号生成回路107によってクロック信号の立ち上がり、立ち下がり波形を変えて、制御信号生成回路107よりも後段のMOSトランジスタをゆっくりとオン、またはオフさせることができる。MOSトランジスタがゆっくりオン、オフすることにより、クロックドライバは、スイッチング動作により急峻なスイッチング電流が流れるのを抑制し、スイッチングノイズを減らすことができる。
第1実施形態の制御信号生成回路107は、電流変化量が最も大きい閾値電圧付近のMOSトランジスタのゲート電圧の立ち上がり、立ち下りをより緩やかにすることで、スイッチング電流の変化量を減らすことができる。
このような第1実施形態の制御信号生成回路107は、「PMOSトランジスタオフ用の制御信号」と、「PMOSトランジスタオン用の制御信号」と、「NMOSトランジスタオフ用の制御信号」と、「NMOSトランジスタオン用の制御信号」と、の4パターンの制御信号を生成することができる。
(1) PMOSトランジスタオフ用の制御信号を出力する場合
・構成
図2は、PMOSトランジスタオフ用の制御信号を出力する制御信号生成回路107の構成を説明するための図である。
制御信号生成回路107は、電源電圧VDDを供給する図示しない電源の端子(以下、単に電源電圧VDDと記す)と接続されている。また、制御信号生成回路107は、図2中に符号「a」を付して示したノードaに一定の電流を流す定電流源204、205を有している。定電流源204、205は、それぞれ同じ値の電流を流すことができる。また、制御信号生成回路107は、コンパレータ206と、ノードaと定電流源204、205とを離接する3つのスイッチ201~203と、遅延部208と、を含んでいる。定電流源204から供給される電流と、定電流源205から供給される電流とは、スイッチ201~203を介して加算される。
遅延部208は、入力信号Vinを遅延させた信号を生成する回路である。遅延部208は、直列に接続された2個のインバータと、インバータに並列接続されたコンデンサと、を含んでいる。スイッチ202には遅延部208によって遅延された信号が入力されるので、スイッチ202はスイッチ201よりも遅れて動作する。
スイッチ207は、NMOSトランジスタによって構成されている。スイッチ207には入力信号Vinが入力される。スイッチ207は、スイッチ201、202と相補的に動作するので、PMOSトランジスタオン用の制御信号を出力することができる。
図3(a)~(d)は、図2に示した制御信号生成回路107の動作を説明するための図である。
図3(a)は、スイッチ201、207、遅延部208に入力される入力信号Vinの電圧を縦軸に示し、横軸に時間tを示したグラフである。図3(b)は、図2に示したノードaの電位を縦軸に、時間tを横軸に示したグラフである。ノードaの電位は、PMOSトランジスタのゲートに印加される電圧VGとなる。図3(c)は、PMOSトランジスタに流れるスイッチング電流IDSを縦軸に、横軸に時間tを示したグラフである。図3(d)は、図3(c)に示したスイッチング電流IDSの時間微分値を縦軸に、横軸に時間tを示したグラフである。
すなわち、図3(a)に示したように、入力信号Vinの電圧がHigh(以下、単に「H」と記す)のとき、スイッチ207がオン状態になっているので、図3(b)に示したように、ノードaの電位は、VSSとなる。
次に、時間t1において入力信号Vinの電圧がH→Low(以下、単に「L」と記す)になると、スイッチ201がオンされ、スイッチ207がオフされる。このとき、スイッチ203はオン状態になっている。このとき、スイッチ202は、遅延部208により遅延された信号によってスイッチングするため、オフ状態である。
また、上記した構成では、定電流源204、205を同じ値の電流を供給する別の定電流源としたが、定電流源204、205を1個の定電流源に置き換えてもよい。
・構成
図4は、PMOSトランジスタオン用の制御信号を出力する制御信号生成回路107の構成を説明するための図である。
制御信号生成回路107は、電源電圧VDDと接続され、ノードに一定の電流を流す定電流源405と、電源電圧VSSと接続され、ノードに一定の電流を流す定電流源404と、を有している。定電流源404、405は、同じ値の電流を供給する定電流源とする。
さらに、制御信号生成回路107は、ノードbと電源電圧VDDとを離接するスイッチ407、を含んでいる。スイッチ407は、PMOSトランジスタによって構成されている。スイッチ407には入力信号Vinが入力され、スイッチ403と相補的に動作するので、PMOSトランジスタオフ用の制御信号を出力することができる。
図5(a)~(d)は、図4に示した制御信号生成回路107の動作を説明するための図である。
図5(a)は、スイッチ403、407、遅延部408に入力される入力信号の電圧Vinを縦軸に示し、横軸に時間tを示したグラフである。図5(b)は、図4に示したノードbの電位を縦軸に、時間tを横軸に示したグラフである。図5(c)は、PMOSトランジスタに流れるスイッチング電流IDSを縦軸に、横軸に時間tを示したグラフである。図5(d)は、図5(c)に示したスイッチング電流IDSの時間微分値を縦軸に、横軸に時間tを示したグラフである。
すなわち、図5(a)に示したように、入力信号Vinの電圧がLのとき、スイッチ407がオン状態になっている。このため、図5(b)に示したように、ノードbの電位は、VDDとなる。
図5(b)に示したように、スイッチ403には、定電流源404から電流が流れ、PMOSトランジスタのゲート容量の電荷が放電される。このため、時間t1~t2の間、ノードbの電位は一定の傾きを持って下降する。
この結果、図5(c)に示したように、PMOSトランジスタのスイッチング電流IDSの変化が緩やかになる。そして、図5(d)に示したように、スイッチング電流IDSの時間微分値は、PMOSトランジスタのゲートがオンする閾値電圧VDD-Vthに達する時間t2の前後で抑制されるため、スイッチングノイズが低減される。
・構成
図6は、NMOSトランジスタオフ用の制御信号を出力する制御信号生成回路107の構成を説明するための図である。
制御信号生成回路107は、電源電圧VSSと接続され、ノードに一定の電流を流す定電流源604、605を有している。定電流源604、605は同じ値の電流を流すことができる。また、制御信号生成回路107は、コンパレータ606と、図6中に符号「c」を付したノードcと定電流源604、605とを離接する3つのスイッチ601~603と、遅延部608と、を含んでいる。スイッチ601~603は、NMOSトランジスタによって構成されている。
さらに、制御信号生成回路107は、ノードcと電源電圧VDDとを離接するスイッチ607、を含んでいる。スイッチ607は、PMOSトランジスタによって構成されている。スイッチ607には入力信号Vinが入力され、スイッチ601、602と相補的に動作するので、NMOSトランジスタオン用の制御信号を出力することができる。
図7(a)~(d)は、図6に示した制御信号生成回路107の動作を説明するための図である。
図7(a)は、スイッチ601、607に入力される入力信号Vinの電圧を縦軸に示し、横軸に時間tを示したグラフである。図7(b)は、図6に示したノードcの電位を縦軸に、時間tを横軸に示したグラフである。ノードcの電位は、NMOSトランジスタのゲートに印加される電圧VGとなる。図7(c)は、NMOSトランジスタに流れるスイッチング電流IDSを縦軸に、横軸に時間tを示したグラフである。図7(d)は、図7(c)に示したスイッチング電流IDSの時間微分値を縦軸に、横軸に時間tを示したグラフである。
すなわち、図7(a)に示したように、入力信号Vinの電圧がLのとき、スイッチ607がオン状態になっている。このため、図7(b)に示したように、ノードcの電位は、VDDとなる。
次に、時間t2において、ノードcの電位が閾値電圧Vth付近まで下降すると、Vc=Vthとなってコンパレータ606から出力される信号が徐々に反転し、スイッチ603が徐々にオフされる。このため、図7(b)に示したように、ノードcの電位は時間t2において閾値電圧Vth付近に達した後、フローティング状態になって、傾きが略ゼロになる。
以上のように、第1実施形態によれば、時間t2における閾値電圧Vth付近のゲート電圧VGの変化が緩やかになる。
また、上記構成では、定電流源604、605を、同じ値の電流を供給する別の定電流源としたが、定電流源604、605を1個の定電流源に置き換えてもよい。
・構成
図8は、NMOSトランジスタオン用の制御信号を出力する制御信号生成回路107の構成を説明するための図である。
制御信号生成回路107は、電源電圧VDDと接続され、ノードに一定の電流を流す定電流源804と、電源電圧VSSと接続され、ノードに一定の電流を流す定電流源805と、を有している。定電流源804、805は、同じ値の電流を供給する定電流源とする。
さらに、制御信号生成回路107は、ノードdと電源電圧VSSとを離接するスイッチ807を含んでいる。スイッチ807は、NMOSトランジスタによって構成されている。スイッチ807には入力電圧Vinが入力され、スイッチ803と相補的に動作するので、NMOSトランジスタオフ用の制御信号を出力することができる。
図9(a)~(d)は、図8に示した制御信号生成回路107の動作を説明するための図である。
図9(a)は、スイッチ803、807、遅延部808に入力される入力電圧Vinを縦軸に示し、横軸に時間tを示したグラフである。図9(b)は、図8に示したノードdの電位を縦軸に、時間tを横軸に示したグラフである。図9(c)は、NMOSトランジスタに流れるスイッチング電流IDSを縦軸に、横軸に時間tを示したグラフである。図9(d)は、図9(c)に示したスイッチング電流IDSの時間微分値を縦軸に、横軸に時間tを示したグラフである。
すなわち、図9(a)に示したように、入力電圧VinがHのとき、スイッチ807がオン状態になっているので、図8(b)に示したように、ノードdの電位は、VSSとなる。
次に、時間t1において、入力電圧VinがH→Lになると、スイッチ803がオンし、スイッチ807はオフする。このとき、スイッチ802はオフ状態になっている。また、スイッチ801は、遅延部808により遅延された信号によってスイッチングするため、オン状態である。図5(b)に示したように、スイッチ803には、定電流源804から電流が流れる。このとき、NMOSトランジスタのゲート容量に電荷が充電されるので、時間t1~t2の間、ノードdの電位は一定の傾きを持って上昇する。
スイッチ801とスイッチ803とがオンしている時間t2~t3の間、スイッチ803には定電流源804から供給される電流が流れる。また、スイッチ801、802には、定電流源804から供給される電流と同じ値の電流が定電流源805から流れる。このため、図9(b)に示したように、ノードdの電位は閾値電圧Vthに維持され、傾きが略ゼロになる。
その結果、図9(c)、(d)に示したように、スイッチング電流IDSの時間微分値は、NMOSトランジスタのゲートがオンする閾値電圧Vthに達する時間t2の前後で抑制される。このため、第1実施形態では、スイッチングノイズが低減される。
さらに、第1実施形態は、上記した構成に限定されるものはなく、例えば、図8に示した遅延部808がない構成としてもよい。このとき、定電流源804を定電流源805よりも大きな値の電流を流すようにし、スイッチ801は入力信号Vinと位相が逆の信号により制御する。
次に、本発明の第2実施形態について説明する。
図10は、第2実施形態の制御信号生成回路1007を説明するための図である。第2実施形態は、図10に示したPMOSトランジスタを、ダイオード接続されたスイッチによって制御する点で第1実施形態と相違する。なお、図10は、制御信号生成回路1007が、PMOSトランジスタオフ用の制御信号を出力する場合を例にあげる。
106 クロック信号生成回路
107 制御信号生成回路
109、110 コンデンサ
101~104 MOSトランジスタ
201~203、207、401~403、407、601~603、607、801~803、807、1001~1003、1006、1007、1010 スイッチ
204、205、404、405、604、605、804、805、1004、1005、1009 定電流源
206、406、606、806 コンパレータ
208、408、608、808 遅延部
Claims (13)
- MOSトランジスタのゲートを制御するための制御信号を生成する制御信号生成回路であって、
電流源と前記ゲートに接続され、入力信号に基づいて制御される第1スイッチ部と、
前記電流源と前記ゲートに接続され、前記入力信号及び前記制御信号に基づいて制御される第2スイッチ部と、
を備え、
前記制御信号の電圧値が前記入力信号に基いて遷移し、前記電圧値の時間に対する傾きは、前記電圧値が前記MOSトランジスタの閾値電圧以下であるときよりも、前記電圧値が前記MOSトランジスタの閾値電圧を越えた後に小さくなるように切り換わることを特徴とする制御信号生成回路。 - 前記第1スイッチ部は、
前記入力信号によりオンオフ制御される第1スイッチを備え、
前記第2スイッチ部は、
前記入力信号によりオン、オフ制御される第2スイッチと、前記制御信号に基づき前記第2スイッチに流れる電流を制御する出力制御部と、
を備えることを特徴とする請求項1に記載の制御信号生成回路。 - 前記電流源は、前記第1スイッチ及び第2スイッチに等しい値の電流を供給することを特徴とする請求項1に記載の制御信号生成回路。
- 前記電流源は、前記第1スイッチに電流を供給する第1電流源と、前記第2スイッチに、前記第1電流源によって供給される電流と値が異なる電流を供給する第2電流源と、を備えることを特徴とする請求項1に記載の制御信号生成回路。
- 前記出力制御部は、
前記制御信号の電圧値と前記MOSトランジスタの閾値とを比較する比較器と、前記比較器の比較結果によりオンオフ制御される第3スイッチと、を備えることを特徴とする請求項2に記載の制御信号生成回路。 - 前記第3スイッチは、前記MOSトランジスタがオン状態からオフ状態になったとき、前記第2スイッチに電流が流れることを止めることを特徴とする請求項5に記載の制御信号生成回路。
- 前記第3スイッチは、前記MOSトランジスタがオフ状態からオン状態になったとき、流れることを止められていた前記電流を、前記第2スイッチに流すことを特徴とする請求項6に記載の制御信号生成回路。
- 前記出力制御部は、ダイオードを備えることを特徴とする請求項2に記載の制御信号生成回路。
- 前記入力信号を遅延させた遅延信号を生成する遅延部をさらに備え、
前記第1スイッチ部は、前記遅延信号に従って動作し、前記ゲートに電流を供給可能であることを特徴とする請求項1に記載の制御信号生成回路。 - 前記入力信号を遅延させた遅延信号を生成する遅延部をさらに備え、
前記第2スイッチ部は、前記遅延信号に従って動作し、前記ゲートに電流を供給可能であることを特徴とする請求項1に記載の制御信号生成回路。 - 前記請求項1~10のいずれか1項に記載の制御信号生成回路を少なくとも1つ以上備え、
少なくとも1以上の、前記MOSトランジスタと、
前記制御信号生成回路、前記MOSトランジスタにより充放電される容量素子と、
を備えることを特徴とするチャージポンプ駆動回路。 - 前記請求項1~10のいずれか1項に記載の制御信号生成回路を備え、
前記制御信号生成回路から出力されるクロック信号に基づいて、前記制御信号生成回路よりも後段に設けられた前記MOSトランジスタを駆動することを特徴とするクロックドライバ。 - 少なくとも1以上のMOSトランジスタと、該MOSトランジスタにより充放電される容量素子と、を有するチャージポンプを駆動するチャージポンプの駆動方法であって、
入力信号に基づく傾きで遷移し、前記入力信号が前記MOSトランジスタの閾値を越えるとき、前記入力信号が前記MOSトランジスタの閾値以下であるときよりも前記傾きが小さい値に切り換わる制御信号を生成し、
前記入力信号及び前記制御信号に基づいて前記MOSトランジスタのゲートに電流を供給することを特徴とするチャージポンプの駆動方法。
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US13/810,002 US20130113526A1 (en) | 2011-03-30 | 2012-03-28 | Control signal generation circuit, charge pump drive circuit, clock driver, and drive method of charge pump |
EP12763752.8A EP2587649A4 (en) | 2011-03-30 | 2012-03-28 | CONTROL SIGNAL GENERATION CIRCUIT, LOAD PUMP DRIVEN CIRCUIT, CLOCK DRIVER AND METHOD FOR DRIVING A LOAD PUMP |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005192350A (ja) | 2003-12-26 | 2005-07-14 | Matsushita Electric Ind Co Ltd | 降圧式チャージポンプタイプ型電源回路およびモノリシック集積回路 |
JP2007505596A (ja) * | 2003-09-08 | 2007-03-08 | ペレグリン セミコンダクター コーポレーション | チャージポンプ装置及び出力電源生成方法 |
JP2008099370A (ja) * | 2006-10-06 | 2008-04-24 | Texas Instr Japan Ltd | 電源回路およびバッテリ装置 |
Family Cites Families (6)
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JP3666843B2 (ja) * | 1999-02-26 | 2005-06-29 | 株式会社東芝 | 絶縁ゲート型半導体素子のゲート回路 |
US6459324B1 (en) * | 2000-10-23 | 2002-10-01 | International Rectifier Corporation | Gate drive circuit with feedback-controlled active resistance |
EP1610292B1 (en) * | 2004-06-25 | 2016-06-15 | Semiconductor Energy Laboratory Co., Ltd. | Display device, driving method thereof and electronic device |
US7479770B2 (en) * | 2005-04-28 | 2009-01-20 | Texas Instruments Incorporated | System and method for driving a power field-effect transistor (FET) |
DE102006036349B4 (de) * | 2006-08-03 | 2015-04-02 | Infineon Technologies Ag | Schaltungsvorrichtung und Verfahren zum Erkennen eines Betriebszustandes |
US7554367B2 (en) * | 2006-11-22 | 2009-06-30 | System General Corp. | Driving circuit |
-
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007505596A (ja) * | 2003-09-08 | 2007-03-08 | ペレグリン セミコンダクター コーポレーション | チャージポンプ装置及び出力電源生成方法 |
JP2005192350A (ja) | 2003-12-26 | 2005-07-14 | Matsushita Electric Ind Co Ltd | 降圧式チャージポンプタイプ型電源回路およびモノリシック集積回路 |
JP2008099370A (ja) * | 2006-10-06 | 2008-04-24 | Texas Instr Japan Ltd | 電源回路およびバッテリ装置 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10447152B2 (en) | 2016-07-15 | 2019-10-15 | Linear Technology Corporation | Driving charge pump circuits |
US10468978B2 (en) | 2016-07-15 | 2019-11-05 | Linear Technology Corporation | Balancing techniques and circuits for charge pumps |
TWI678872B (zh) * | 2016-07-15 | 2019-12-01 | 美商線性科技股份有限公司 | 用於驅動切換式電容器轉換器的電路及方法 |
US10666135B2 (en) | 2016-07-15 | 2020-05-26 | Linear Technology Llc | Balancing charge pump circuits |
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