TW201315120A - Charge pump system capable of stabilizing an output voltage - Google Patents

Abstract

A charge pump system includes a charge pump, a ring oscillator, a comparing circuit and a discharge circuit. When an output voltage of the charge pump is relatively low, the comparing circuit turns on the ring oscillator to make the ring oscillator provide an oscillation output to the charge pump to raise the output voltage of the charge pump. When the output voltage of the charge pump is relatively high, the comparing circuit turns off the ring oscillator to stop the ring oscillator from providing the oscillation output to the charge pump, the comparing circuit also makes the discharge circuit provide a discharge path to the charge pump to quickly reduce the output voltage of the charge pump.

Description

Charge pump system with stable output voltage

The present invention relates to a charge pump system, and more particularly to a charge pump system having a voltage detection function.

Charge pumps are now widely used in electronic circuits. Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a conventional charge pump system 100. The charge pump system 100 includes a charge pump 14 , an oscillator 16 , a comparator 18 , a first resistor 11 and a second resistor . 12. Charge pump 14 is coupled to input voltage V _DD and receives a signal from oscillator 16 to provide an output voltage V _OUT . The charge pump system 100 generates a second resistance voltage V _R2 by the current flowing to the first resistor 11 and the second resistor 12 to compare the second resistor voltage V _R2 with the reference voltage V _ref through the comparator 18 to control the oscillation. Actuator 16 is activated.

However, the current flowing to the first resistor 11 and the second resistor 12 may cause a leakage phenomenon, resulting in a situation in which the output voltage V _OUT tends to have insufficient voltage or the output voltage is unstable. A common improvement method is to increase the resistance values of the first resistor 11 and the second resistor 12, but when the resistance values of the first resistor 11 and the second resistor 12 increase, the output voltage V _{OUT is} seriously delayed. The charge pump system 100 is not ideal in practical applications.

One embodiment of the present invention provides a charge pump system including a charge pump, a ring oscillator, a comparison circuit, and a discharge circuit. The charge pump includes an output terminal for providing an output voltage. The output of the ring oscillator is coupled to the control terminal of the charge pump for providing an oscillation output to the charge pump. The comparison circuit includes a a first impedance and a second impedance and a comparator, the first end of the first impedance is coupled to the output end of the charge pump, and the first end of the second impedance is coupled to the second end of the first impedance The second end of the second impedance is grounded. The comparator includes a first input end, a second input end, and an output end. The first input end is coupled to the second end of the first impedance. The second input terminal is configured to receive a reference voltage. The discharge circuit includes a first switch, a second switch, and a third impedance. The first end of the first switch is coupled to the output of the charge pump. The control end of the first switch is coupled to the output end of the comparator; the first end of the second switch is coupled to the second end of the first switch, and the second end of the second switch is Grounding; the first end of the third impedance is coupled to the output end of the charge pump, and the second end is Connected to the control terminal of the second switch.

Another embodiment of the present invention provides a charge pump system including a charge pump, a ring oscillator, and a comparison circuit; the charge pump includes an output terminal for providing an output voltage; an output of the ring oscillator The end is coupled to the control end of the charge pump for providing an oscillating output to the charge pump; the comparison circuit includes a first impedance, a second impedance, and a comparator; the first end of the first impedance The first end of the second impedance is coupled to the second end of the first impedance, and the second end is coupled to the output end of the charge pump; the comparator includes a first end An input end, a second input end, and an output end; the first input end is coupled to the second end of the first impedance; the second input end is configured to receive a reference voltage; the charging circuit includes a first a switch, a second switch, and a third impedance; the first end of the first switch is coupled to the bias source; the first end of the second switch is coupled to the second end of the first switch The control end is coupled to the output of the comparator, and the second end is coupled to the charge The output terminal; and a first end of the third impedance of the line coupled to the control terminal of the first switch, a second terminal coupled to the output terminal of the charge pump.

The charge pump system of the present invention has the characteristics of fast charging or discharging function and low leakage current, and can provide a stable and low-delay output voltage.

Please refer to FIG. 2 , which is a schematic diagram of a charge pump system 200 according to a first embodiment of the present invention. The charge pump system 200 includes a charge pump 24 , a ring oscillator 26 , a comparison circuit 250 , and a discharge circuit 260 . The charge pump 24 includes an input terminal 20 for receiving an input voltage V _DD and an output terminal 222 for providing an output voltage V _OUT . The output terminal 223 of the ring oscillator 26 is coupled to the charge pump 24 . The control terminal 221 is configured to provide an oscillating output to the charge pump 24. The comparison circuit 250 includes a first impedance 21, a second impedance 22, and a comparator 28. The first end of the first impedance 21 is coupled to the output end 222 of the charge pump 24, and the first end of the second impedance 22 is The second end of the second impedance 22 is grounded; the comparator 28 includes a first input end 211, a second input end 212, and an output end 213, the first input The end 211 is coupled to the second end of the first impedance 21, the second input end 212 is configured to receive a reference voltage V _ref , and the output end 213 of the comparator 28 is coupled to the input end of the ring oscillator 26 . 224. The discharge circuit 260 includes a first switch 201, a second switch 202, and a third impedance 203. The first end of the first switch 201 is coupled to the output end 222 of the charge pump 24. The control end of the first switch 201 is The first end of the second switch 202 is coupled to the second end of the first switch 201, the second end of the second switch 202 is grounded, and the second switch 202 is a The NMOS transistor is continuously kept open; the first end of the third impedance 203 is coupled to the output end 222 of the charge pump 24, the second end is coupled to the control end of the second switch 202, and the third impedance 203 It is used to provide a voltage drop to deal with the undervoltage of the second switch 202. The first impedance 21 and the second impedance 22 can be any of a two-resistor, a two-capacitor, a two-NMOS transistor, a two-PMOS transistor, and a diode, and the third impedance 203 can be a resistor, a capacitor, or a diode. Any of them.

When the charge pump 24 pulls the output voltage V _OUT of the output terminal 222 to a high potential, the voltage division between the first impedance 21 and the second impedance 22 received by the first input terminal 211 is greater than the reference. The voltage V _ref , therefore the output 213 of the comparator 28 will output a high potential, and the first switch 201 is turned on. When the output 213 of the comparator 28 outputs a high potential, the operation of the ring oscillator 26 is stopped, and the charge pump 24 is stopped to continue to pull up the potential of the output voltage V _OUT of its output terminal 222, so that the charge pump system 200 reaches The effect of saving electricity. On the other hand, when the first switch 201 is turned on, the output voltage V _OUT is discharged by the current flowing to the first switch 201 until the first input terminal 211 receives the first impedance and the second impedance. When the voltage drops below the reference voltage V _ref , the output terminal 213 of the comparator 28 outputs a low potential, and the first switch 201 is turned off. When the output 213 of the comparator 28 outputs a low potential, the ring oscillator 26 is controlled to start operating, and the output voltage V _OUT of the output terminal 222 of the charge pump 24 is again pulled up.

In the second figure, the first input terminal 211 of the comparator 28 is a positive input terminal, the second input terminal 212 is a negative input terminal, and the first switch 201 is an NMOS transistor; please refer to FIG. 3 is a schematic diagram of a charge pump system 300 according to a second embodiment of the present invention. The difference between the charge pump system 300 and the charge pump system 200 is that the first input terminal 311 of the comparator 38 is a negative input terminal, and the second input is The end system 312 is a positive input terminal, and the first switch 301 is a PMOS transistor. In the embodiment of FIG. 3, when the charge pump 24 pulls the output voltage V _OUT of the output terminal 222 to a high potential, the first input terminal 211 receives the first impedance 21 and the second impedance. The divided voltage between 22 will be greater than the reference voltage V _ref , so the output 313 of the comparator 38 will output a low potential and the first switch 301 will be turned on. When the output terminal 313 of the comparator 38 outputs a low potential, the operation of the ring oscillator 26 is stopped, and the charge pump 24 is stopped from continuing to pull up the output voltage V _{OUT of} its output terminal 222, so that the charge pump system 300 reaches the power saving state. effect. On the other hand, when the first switch 301 is turned on, the output voltage V _OUT is discharged by the current flowing to the first switch 301 until the first input terminal 311 receives the first impedance 21 and the second impedance 22 When the divided voltage falls below the reference voltage V _ref , the output terminal 313 of the comparator 38 outputs a high potential, and the first switch 301 is turned off. When the output 313 of the comparator 38 outputs a high potential, the ring oscillator 26 is controlled to start operating, and the output voltage V _OUT of the output terminal 222 of the charge pump 24 is pulled up again.

Please refer to FIG. 4. FIG. 4 is a schematic diagram of a charge pump system 400 according to a third embodiment of the present invention. The charge pump system 400 differs from the charge pump system 200 in that the charge pump system 400 further includes a fourth impedance 204. One end is coupled to the second end of the third impedance 203, and the second end is grounded. The third impedance 203 and the fourth impedance 204 are used to provide a voltage drop to handle the undervoltage of the second switch 202, and the third impedance 203 and the fourth impedance 204 must be resistors, capacitors, and diodes. Either. In the third embodiment, the third impedance 203 and the fourth impedance 204 are the two capacitors, so that the leakage current from the output voltage V _OUT to the ground through the third impedance 203 and the fourth impedance 204 in the discharge circuit 260 can be avoided. .

Please refer to FIG. 5. FIG. 5 is a schematic diagram of a charge pump system 500 according to a fourth embodiment of the present invention. The difference between the charge pump system 500 and the charge pump system 200 is that the ring oscillator 26 of the charge pump system 500 is not coupled to Output 213 of comparator 28. Although the charge pump system 200 can control the operation of the charge pump 24 via the sequential start and stop operations of the ring oscillator 26 to achieve the power saving effect of the charge pump system 200, the ring oscillator 26 is in a stopped state. There is usually a delay in returning to a state of oscillation. With the setting of the charge pump system 500, since the ring oscillator 26 is continuously operated, the output voltage V _OUT of the output terminal 222 of the charge pump 24 can be prevented from being delayed.

In the first embodiment to the fourth embodiment, the first impedance 21 and the second impedance 22 are the two capacitances, and in the comparison circuit 250, the current is prevented from the output end 222 of the charge pump 24 via the first impedance 21 . And the second impedance 22 flows to the ground, thereby stabilizing the output voltage V _OUT .

Please refer to FIG. 6. FIG. 6 is a schematic diagram of a charge pump system 600 according to a fifth embodiment of the present invention. The charge pump system 600 includes a charge pump 64, a ring oscillator 66, a comparison circuit 650, and a charging circuit 660. The charge pump 64 includes an input 60 for receiving an input voltage V _DD , an output 622 for providing an output voltage -V _OUT , and an output 623 of the ring oscillator 66 coupled to the charge pump 64 for control Terminal 621 is for providing an oscillating output to charge pump 64. The comparison circuit 650 includes a first impedance 61, a second impedance 62, and a comparator 68. The first end of the first impedance 61 is coupled to a bias voltage source V _bias ; the first end of the second impedance 62 is coupled to the second end of the first impedance 61, and the second end of the second impedance 62 is The output terminal 622 is coupled to the output of the charge pump 64. The comparator 68 includes a first input terminal 611, a second input terminal 612, and an output terminal 613. The first input end 611 is coupled to the second end of the first impedance 61; the second input end 612 is configured to receive a reference voltage V _ref ; the output end 613 of the comparator 68 is coupled to the ring oscillator 66 Input 624. The charging circuit 660 includes a first switch 601, a second switch 602, and a third impedance 603. The first end of the first switch 601 is coupled to the bias source V _bias , and the first switch 601 is a PMOS transistor that is kept open; the first end of the second switch 602 is coupled to the first switch The second end of the second switch 602 is coupled to the output end 613 of the comparator 68, and the second end of the second switch 602 is coupled to the output end 622 of the charge pump 64; the third impedance 603 The first end is coupled to the control end of the first switch 601, the second end of the third impedance 603 is coupled to the output end 622 of the charge pump 64, and the third impedance 603 is used to provide a voltage drop for processing The case where the withstand voltage of the first switch 601 is insufficient. The first impedance 61 and the second impedance 62 may be any of a two-resistor, a two-capacitor, a two-NMOS transistor, a two-PMOS transistor, and a diode, and the third impedance 603 may be a resistor, a capacitor, or a diode. Any of them.

When the charge pump 64 pulls the output voltage -V _{OUT of} its output terminal 622 to a low potential, the first input terminal 611 of the comparator 68 receives the first impedance 61 and the second impedance 62. The voltage will be less than the reference voltage V _ref , so the output 613 of the comparator 68 will output a high potential and the second switch 602 will be turned on. When the output 613 of the comparator 68 outputs a high potential, the operation of the ring oscillator 66 is stopped, and the charge pump 64 is stopped to continue to pull down the potential of the output voltage -V _OUT of its output terminal 622, so that the charge pump system 600 reaches The effect of saving electricity. On the other hand, when the second switch 602 is turned on, the bias source V _bias will start to charge the output voltage -V _OUT by the current flowing to the first switch 601 until the first input 611 receives the first impedance 611. When the divided voltage between the second impedance 622 and the second impedance 622 is greater than the reference voltage V _ref , the output terminal 613 of the comparator 68 is outputted to a low potential, and the second switch 602 is turned off. When the output 613 of the comparator 68 outputs a low potential, the ring oscillator 66 is controlled to start operating, and the charge pump 64 again pulls down the output voltage -V _{OUT of} its output terminal 622.

In Fig. 6, the first input terminal 611 of the comparator 68 is a negative input terminal, the second input terminal 612 is a positive input terminal, and the second switch 602 is an NMOS transistor; please refer to FIG. 7 is a schematic diagram of a charge pump system 700 according to a sixth embodiment of the present invention. The difference between the charge pump system 700 and the charge pump system 600 is that the first input end 711 of the comparator 78 is a positive input terminal, and the second input is The terminal 712 is a negative input terminal, and the second switch 702 is a PMOS transistor. In the embodiment of the seventh embodiment, when the charge pump 64 pulls the output voltage -V _{OUT of} its output terminal 622 to a low potential, the first input 711 of the comparator 78 receives the first impedance 61 at this time. The divided voltage with the second impedance 62 will be less than the reference voltage V _ref , so the output 713 of the comparator 78 will output a low potential and the second switch 702 will be turned on. When the output 713 of the comparator 78 outputs a low potential, the operation of the ring oscillator 66 is stopped, and the charge pump 64 is stopped to continue to pull down the potential of the output voltage -V _OUT of its output terminal 622, so that the charge pump system 700 reaches The effect of saving electricity. On the other hand, when the second switch 702 is turned on, the bias source V _bias will start to charge the output voltage -V _OUT by the current flowing to the first switch 601 until the first input 711 receives the first impedance 611. When the divided voltage between the second impedance 622 and the second impedance 622 is greater than the reference voltage V _ref , the output terminal 713 of the comparator 78 is outputted to a high potential, and the second switch 702 is turned off. When the output 713 of the comparator 78 outputs a high potential, the ring oscillator 66 is controlled to start operating, and the charge pump 64 again pulls down the output voltage -V _{OUT of} its output terminal 622.

Please refer to FIG. 8. FIG. 8 is a schematic diagram of a charge pump system 800 according to a seventh embodiment of the present invention. The charge pump system 800 differs from the charge pump system 600 in that the charge pump system 800 further includes a fourth impedance 604. The first end of the fourth impedance 604 is coupled to the bias source V _bias , and the second end is coupled to the first end of the third impedance 603 . The third impedance 603 and the fourth impedance 604 are used to provide a voltage drop to handle the undervoltage of the first switch 601, and the third impedance 603 and the fourth impedance 604 must be two resistors, two capacitors, and two Any of the polar bodies. In the seventh embodiment, the third impedance 603 and the fourth impedance 604 are the two capacitances, so that in the charging circuit 660, the current from the first end of the fourth impedance 604 is passed through the fourth impedance 604 and the third impedance. 603 flows to the ground.

Please refer to FIG. 9. FIG. 9 is a schematic diagram of a charge pump system 900 according to an eighth embodiment of the present invention. The charge pump system 900 differs from the charge pump system 600 in that the ring oscillator 66 of the charge pump system 900 is not coupled to Output 613 of comparator 68. Although the charge pump system 600 can control the operation of the charge pump 64 via the sequential start and stop operations of the ring oscillator 66 to achieve the power saving effect of the charge pump system 600, the ring oscillator 66 is in a stopped state. There is usually a delay in returning to a state of oscillation. With the setting of the charge pump system 900, since the ring oscillator 66 is continuously operated, the output voltage -V _OUT of the output terminal 622 of the charge pump 64 can be prevented from being delayed.

In the fifth embodiment to the eighth embodiment, the first impedance 61 and the second impedance 62 are two capacitors, and in the comparison circuit 650, the current is prevented from the first end of the first impedance 61 via the first impedance. 61 and 64 the second impedance 62 to an output terminal of the charge pump 622, so as to stabilize the output voltage -V _OUT.

Please refer to FIG. 10, which is a schematic diagram of a charge pump system 1000 according to a ninth embodiment of the present invention. The charge pump system 1000 is a first impedance 21 and a second impedance 22 of the charge pump system 200 respectively. Embodiments implemented by crystal 1001 and a second NMOS transistor 1002. As shown in FIG. 10, if the first impedance 21 and the second impedance 22 are implemented by the first NMOS transistor 1001 and the second NMOS transistor 1002, the drain of the first NMOS transistor 1001 is coupled to the first NMOS. The gate of the transistor 1001 is coupled to the gate of the second NMOS transistor 1002. The drain of the first NMOS transistor 1001 is coupled to the output terminal 222 of the charge pump 24, and the drain of the second NMOS transistor 1002 is coupled to the source of the first NMOS transistor 1001 to the first of the comparator 28. The input terminal 211 and the source of the second NMOS transistor 1002 are coupled to the ground. Since the components of the first NMOS transistor 1001 and the second NMOS transistor 1002 are small in volume, the volume of the charge pump system 1000 can be effectively reduced.

Please refer to FIG. 11. FIG. 11 is a schematic diagram of a charge pump system 1100 according to a tenth embodiment of the present invention. The charge pump system 1100 is a first impedance 61 and a second impedance 62 of the charge pump system 600 respectively. Embodiments are implemented by crystal 1101 and a second NMOS transistor 1102. As shown in FIG. 11 , if the first impedance 61 and the second impedance 62 are respectively implemented by the first NMOS transistor 1101 and the second NMOS transistor 1102, the drain of the first NMOS transistor 1101 is coupled to the first NMOS. The gate of the second NMOS transistor 1102 is coupled to the gate of the second NMOS transistor 1102. The drain of the first NMOS transistor 1101 is coupled to the bias source V _bias , and the source of the first NMOS transistor 1101 and the drain of the second NMOS transistor 1102 are coupled to the first input of the comparator 68 . 611 , and the source of the second NMOS transistor 1102 is coupled to the output end 622 of the charge pump 64 . Since the components of the first NMOS transistor 1101 and the second NMOS transistor 1102 are small in volume, the volume of the charge pump system 1100 can be effectively reduced.

Please refer to FIG. 12, which is a schematic diagram of a charge pump system 1200 according to an eleventh embodiment of the present invention. The charge pump system 1200 is a first impedance 21 and a second impedance 22 of the charge pump system 200 respectively. Embodiments implemented by transistor 1201 and a second PMOS transistor 1202. As shown in FIG. 12, if the first impedance 21 and the second impedance 22 are implemented by the first PMOS transistor 1201 and the second PMOS transistor 1202, the drain of the first PMOS transistor 1201 is coupled to the first PMOS. The gate of the transistor 1201 is coupled to the gate of the second PMOS transistor 1202. The source of the first PMOS transistor 1201 is coupled to the output terminal 222 of the charge pump 24, and the source of the second PMOS transistor 1202 is coupled to the first pole of the first PMOS transistor 1201 to the first of the comparator 28. The input terminal 211 and the drain of the second PMOS transistor 1202 are coupled to the ground end. Since the components of the first PMOS transistor 1201 and the second PMOS transistor 1202 are small in volume, the volume of the charge pump system 1200 can be effectively reduced.

Please refer to FIG. 13. FIG. 13 is a schematic diagram of a charge pump system 1300 according to a twelfth embodiment of the present invention. The charge pump system 1300 is a first impedance 61 and a second impedance 62 of the charge pump system 600 respectively as a first PMOS. An embodiment implemented by a transistor 1301 and a second PMOS transistor 1302. As shown in FIG. 13 , if the first impedance 61 and the second impedance 62 are respectively implemented by the first PMOS transistor 1301 and the second PMOS transistor 1302 , the drain of the first PMOS transistor 1301 is coupled to the first PMOS. The gate of the transistor 301 is coupled to the gate of the second PMOS transistor 1302. The source of the first PMOS transistor 1301 is coupled to the bias source V _bias , and the drain of the first PMOS transistor 1301 and the source of the second PMOS transistor 1302 are coupled to the first input of the comparator 68 . 611 , and the drain of the second PMOS transistor 1302 is coupled to the output end 622 of the charge pump 64 . Since the components of the first PMOS transistor 1301 and the second PMOS transistor 1302 are small in volume, the volume of the charge pump system 1300 can be effectively reduced.

The present invention is designed to rapidly discharge the charge pump system 200, 300, 400, 500, 1000, 1200 through the design of the discharge circuit 260 in the charge pump system 200, 300, 400, 500, 1000, 1200; in the charge pump system 200, 300 In 400 and 500, the first impedance 21 and the second impedance 22 are two capacitors, and the current in the comparison circuit 250 can be effectively reduced from the output end 222 of the charge pump 24 to the ground via the first impedance 21 and the second impedance 22. The terminal, in turn, stabilizes the output voltage V _OUT . In the charge pump system 500, the arrangement through the loop-type oscillator 26 that is not coupled to the output 213 of the comparator 28 prevents the loop oscillator 26 from being delayed due to restart. In the charge pump system 1000, the first impedance 21 and the second impedance 22 are respectively configured by the first NMOS transistor 1001 and the second NMOS transistor 1002, and the volume of the charge pump system 1000 can be effectively reduced. In the charge pump system 1200, the first impedance 21 and the second impedance 22 are respectively configured by the first PMOS transistor 1201 and the second PMOS transistor 1202, and the volume of the charge pump system 1200 can be effectively reduced.

Moreover, the present invention is designed to rapidly charge the charge pump system 600, 700, 800, 900, 1100, 1300 through the design of the charge circuit 660 in the charge pump system 600, 700, 800, 900, 1100, 1300; in the charge pump system 600 In 700, 800, and 900, the first impedance 61 and the second impedance 62 are two capacitors, which can effectively reduce the current in the comparison circuit 650 from the first end of the first impedance 61 via the first impedance 61 and the second impedance. 62 to 64 of the charge pump output terminal 622, so as to stabilize the output voltage -V _OUT; charge pump system 900, not through the ring oscillator 66 is provided coupled to the output 68 of the comparator 613 of the terminal, can be avoided ring oscillator 66 Delay due to restart. In the charge pump system 1100, the first impedance 61 and the second impedance 62 are respectively configured by the first NMOS transistor 1101 and the second NMOS transistor 1102, and the volume of the charge pump system 1100 can be effectively reduced. In the charge pump system 1300, the first impedance 61 and the second impedance 62 are respectively configured by the first PMOS transistor 1301 and the second PMOS transistor 1302, and the volume of the charge pump system 1300 can be effectively reduced.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

V _OUT , -V _OUT . . . The output voltage

V _DD . . . Input voltage

V _R2 . . . Second resistance voltage

V _ref . . . Reference voltage

V _bias . . . Bias source

11. . . First resistance

12. . . Second resistance

14, 24, 64. . . Charge pump

16. . . Oscillator

18, 28, 38, 68, 78. . . Comparators

20, 60, 224, 624. . . Input

21, 61. . . First impedance

22, 62. . . Second impedance

26, 66. . . Ring oscillator

100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300. . . Charge pump system

201, 301, 601. . . First switch

202, 602, 702. . . Second switch

203, 603. . . Third impedance

204, 604. . . Fourth impedance

211, 311, 611, 711. . . First input

212, 312, 612, 712. . . Second input

213, 222, 223, 313, 613, 622, 623, 713. . . Output

221, 621. . . Control terminal

250, 650. . . Comparison circuit

260. . . Discharge circuit

660. . . Charging circuit

1001, 1101. . . First NMOS transistor

1002, 1102. . . Second NMOS transistor

1201, 1301. . . First PMOS transistor

1202, 1302. . . Second PMOS transistor

Figure 1 is a schematic illustration of a conventional charge pump system.

Fig. 2 is a schematic view showing a charge pump system of a first embodiment of the present invention.

Figure 3 is a schematic illustration of a charge pump system in accordance with a second embodiment of the present invention.

Figure 4 is a schematic illustration of a charge pump system in accordance with a third embodiment of the present invention.

Fig. 5 is a schematic view showing a charge pump system of a fourth embodiment of the present invention.

Figure 6 is a schematic view of a charge pump system in accordance with a fifth embodiment of the present invention.

Figure 7 is a schematic view of a charge pump system in accordance with a sixth embodiment of the present invention.

Figure 8 is a schematic view of a charge pump system of a seventh embodiment of the present invention.

Figure 9 is a schematic view of a charge pump system in accordance with an eighth embodiment of the present invention.

Figure 10 is a schematic illustration of a charge pump system in accordance with a ninth embodiment of the present invention.

Figure 11 is a schematic view of a charge pump system of a tenth embodiment of the present invention.

Figure 12 is a schematic view of a charge pump system in accordance with an eleventh embodiment of the present invention.

Figure 13 is a schematic view showing a charge pump system of a twelfth embodiment of the present invention.

V _OUT . . . The output voltage

V _DD . . . Input voltage

V _ref . . . Reference voltage

20,224. . . Input

twenty one. . . First impedance

twenty two. . . Second impedance

twenty four. . . Charge pump

26. . . Ring oscillator

28. . . Comparators

200. . . Charge pump system

201. . . First switch

202. . . Second switch

203. . . Third impedance

211. . . First input

212. . . Second input

213, 222, 223. . . Output

221. . . Control terminal

250. . . Comparison circuit

260. . . Discharge circuit

Claims (26)

A charge pump system comprising: a charge pump comprising an output for providing an output voltage; a ring oscillator having an output coupled to the control terminal of the charge pump for providing an oscillation to the charge pump An output circuit includes: a first impedance coupled to the output end of the charge pump; a second impedance coupled to the second end of the first impedance, a second The terminal is grounded; and a comparator includes: a first input end coupled to the second end of the first impedance; a second input end for receiving a reference voltage; and an output end; The discharge circuit includes: a first switch having a first end coupled to the output end of the charge pump, a control end coupled to the output end of the comparator; a second switch having a first end coupled to the first end a second end of the switch, the second end is grounded; and a third impedance, the first end of which is coupled to the output end of the charge pump, and the second end is coupled to the control end of the second switch. The charge pump system of claim 1, wherein the first input end of the comparator is a positive input terminal, and the second input end of the comparator is a negative input terminal, the first open relationship is an NMOS Transistor. The charge pump system of claim 1, wherein the first input of the comparator is a negative input, and the second input of the comparator is a positive input, the first open relationship is a PMOS Transistor. The charge pump system of claim 1, wherein the second open relationship is an NMOS transistor. The charge pump system of claim 1, further comprising a fourth impedance, the first end of which is coupled to the second end of the third impedance, and the second end is grounded. The charge pump system of claim 5, wherein the third impedance and the fourth impedance are two resistors. The charge pump system of claim 5, wherein the third impedance and the fourth impedance are two capacitors. The charge pump system of claim 5, wherein the third impedance and the fourth impedance are diodes. A charge pump system comprising: a charge pump comprising an output for providing an output voltage; a ring oscillator having an output coupled to the control terminal of the charge pump for providing an oscillation to the charge pump And a comparison circuit comprising: a first impedance, the first end of which is coupled to a bias source; a second impedance, the first end of which is coupled to the second end of the first impedance, the second end And a comparator, comprising: a first input end coupled to the second end of the first impedance; a second input end for receiving a reference voltage; and a And a charging circuit comprising: a first switch having a first end coupled to the bias source; a second switch having a first end coupled to the second end of the first switch, the control end The second end is coupled to the output end of the charge pump, and the third end is coupled to the control end of the first switch, and coupled to the second end To the output of the charge pump. The charge pump system of claim 9, wherein the first input of the comparator is a negative input, the second input of the comparator is a positive input, and the second open relationship is an NMOS Transistor. The charge pump system of claim 9, wherein the first input of the comparator is a positive input, the second input of the comparator is a negative input, and the second open relationship is a PMOS Transistor. The charge pump system of claim 9, wherein the first switch is a PMOS transistor. The charge pump system of claim 9, wherein the second end of the third impedance is coupled to the output of the charge pump. The charge pump system of claim 1 or 9, wherein the output of the comparator is coupled to the input of the ring oscillator. The charge pump system of claim 1 or 9, wherein the first impedance and the second impedance are two resistors. The charge pump system of claim 1 or 9, wherein the first impedance and the second impedance are two capacitors. The charge pump system of claim 1 or 9, wherein the first impedance and the second impedance are diodes. The charge pump system of claim 1 or 9, wherein the first impedance and the second impedance are two NMOS transistors, and the drain of each NMOS transistor is coupled to the gate. The charge pump system of claim 1 or 9, wherein the first impedance and the second impedance are two PMOS transistors, and the drain of each PMOS transistor is coupled to the gate. The charge pump system of claim 1 or 9, wherein the third impedance is a resistor. The charge pump system of claim 1 or 9, wherein the third impedance is a capacitor. The charge pump system of claim 1 or 9, wherein the third impedance is a diode. The charge pump system of claim 9, further comprising a fourth impedance, the first end of which is coupled to the bias source, and the second end is coupled to the first end of the third impedance. The charge pump system of claim 23, wherein the third impedance and the fourth impedance are two resistors. The charge pump system of claim 23, wherein the third impedance and the fourth impedance are two capacitors. The charge pump system of claim 23, wherein the third impedance and the fourth impedance are diodes.