JPH11220872A - Drive circuit for charge pumping circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a drive circuit which does not consume a current wastefully when its operating temperature is low, and which prevents a drop in the capability of the step-up voltage of a cherge pumping circuit when its operating temperature is high. SOLUTION: A drive circuit is provided with a constant current-source circuit 10 in which a current amount is increased according to a rise in a temperature, i.e., which generates a constant current T1 having a positive temperature coefficiency and with an oscillation circuit 20 which increases an oscillation frequency according to a rise in a temperature according to the constant current T1 generated by the constant current-source circuit 10, i.e., which generates a clock pulse at an oscillation frequency having a positive temperature coefficiency and which supplies the clock pulse to a charge pumping circuit 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit of a charge pump circuit for boosting a voltage inside an LSI in a semiconductor integrated circuit, and more particularly to an increase in current consumption due to an excessive charge pump capacity at a low operating temperature. The present invention also relates to a drive circuit for a charge pump circuit that compensates for a reduction in the capacity of the charge pump boosted voltage output when the operating temperature is high.

[0002]

2. Description of the Related Art A technology related to a charge pump circuit for boosting a voltage inside an LSI in a semiconductor integrated circuit, which prevents an increase in current consumption due to an excessive charge pump capacity at a low operating temperature and increases the charge pump at a high operating temperature. No literature is available on techniques for compensating for reduced voltage output capability.

[0003] Japanese Patent Application Laid-Open No. Sho 60-62704 discloses a circuit technology capable of controlling a current in a voltage controlled oscillator to select a change in oscillation output frequency due to a temperature change. However, Japanese Patent Application Laid-Open No. 60-62704 discloses a circuit in which the temperature dependence of the oscillation output frequency can be arbitrarily set and controlled by a voltage controlled oscillator (VCO circuit). And their purposes are different.

Further, a circuit technique for compensating for the temperature dependency of the oscillation frequency in a ring oscillator circuit has been described.
(2) JP-A-6-169237. However, Japanese Unexamined Patent Publication No. Hei 6-169237 discloses that a constant current having a positive temperature coefficient is generated by a constant voltage source independent of temperature and a resistor having a negative temperature coefficient, thereby reducing the oscillation frequency of the ring oscillator circuit having a negative temperature coefficient. This is a circuit technique for compensating for a constant value. As in the present invention, a constant current having a positive temperature coefficient drives an oscillation circuit constituting a drive circuit of a charge pump circuit, and the oscillation frequency of the oscillation circuit is positive. This is different from the one that performs the temperature compensation of the charge pump capability of the charge pump circuit by having a configuration having the temperature coefficient of

[0005]

FIG. 6 shows a configuration of a general charge pump circuit. In the figure, NMOS diodes ND0 to NDn are connected to an input terminal 100 and an output terminal 20.
0, and an NMOS diode ND0
To NDn are connected to one ends of capacitors C1 to Cn, respectively, and are connected to nodes C0 to N (n-1).
The other ends of (m + 1) (m is 0 or an integer of 1 or more) are commonly connected, and a clock Φ1 is supplied.
The other end of the capacitor C (2m) (m is an integer equal to or greater than 1) is commonly connected to supply a clock Φ2. A capacitor Cout for removing ripples and a Zener diode DZ functioning as a voltage limiter for preventing excessive boosting are connected in parallel between the output terminal 200 and the ground.

The input terminal 100 is applied with a DC voltage Vin. The clocks Φ1 and Φ2 are clocks output at a tie timing such that high-level periods do not overlap each other, as shown in FIG. 7B, and have an amplitude of Vw. The operation of the charge pump circuit shown in FIG. 6 will be briefly described. NMOS diodes ND0 to ND
Assuming that the threshold voltage of n is VD, the potential of the node N0 is at Vin-VD when the clock .PHI.1 is at a low level, and when the clock .PHI.1 is at a high level and the clock .PHI.2 is at a low level, the nodes N0 to N1 and N2 , N (n-1) to Nn from the node N3,.
The potential of (2m) becomes higher than the node N (2m + 1) by the threshold voltage VD of the NMOS diode (where m is 0 or an integer of 1 or more).

Next, when the clock .PHI.1 falls to a low level, the potentials of the nodes N0, N2,..., N2m,. The potential is higher than when Φ1 was at a low level. Next, when the clock Φ2 changes to the high level, the node N (2m−1) is switched to the node N (2m-1).
m), and when the clock φ2 returns to the low level, a current is supplied from the node N (2m-2) to the node N (2m-1), and the potential of the node N (2m-1) becomes the previous cycle. To rise more. In this way, the potential of each node is increased by (Vw-VD) as shown in FIG. 7A, as compared with the potential of the adjacent node on the input terminal 100 side. That is, FIG.
The output voltage Vout at the output terminal 20 of the charge pump circuit shown in FIG.
VD)

[0008]

Vout = n (Vw−VD) + Vin−VD (1) When the capacitance of the capacitors C1 to Cn is C, the frequency of the clocks Φ1 and Φ2 is f, and the allowable output current value at the output terminal 20 of the charge pump circuit is I _LO ,

[0009]

## EQU2 ## I _LO = (Vw−VD) · C / f (2) The output power Wout at the output terminal 20 at that time is:

[0010]

Wout = Vout · I _LO (3)

The NMO of the charge pump circuit is
The S diode is constituted by an N-channel MOS transistor, and the last stage of the clock generation circuit for supplying clocks Φ1 and Φ2 is constituted by a CMOS inverter composed of an N-channel MOS transistor and a P-channel MOS transistor. Therefore, the threshold voltage VD of the NMOS diode and the amplitudes Vw of the clocks Φ1 and Φ2 output from the CMOS inverter are not constant with changes in temperature but have temperature characteristics. That is, the N-channel MOS transistor and the P-channel MOS transistor have a mutual conductance gm when the ambient temperature becomes high.
Decrease. Therefore, at a high temperature, the threshold voltage VD of the NMOS diode increases, and the amplitude Vw of the clocks Φ1 and Φ2 decreases. Therefore, in the general charge pump circuit shown in FIG. 6, the boosted voltage output capability (charge pump capability) of the charge pump circuit decreases at high temperatures, and the boosted voltage output capability increases at low temperatures. Usually, in order to secure the boosted voltage output capability in the operating temperature range, the charge pump capability must be set in consideration of the decrease in the boosted voltage output capability at high temperatures. In this case, if a regulator circuit that adjusts the boosted voltage output of the charge pump circuit or a zener diode for preventing over-boosting is connected, the output current due to excessive boosted voltage output capability at the time of operating temperature is low. And wasteful current consumption increases.

The present invention has been made in view of such circumstances, and does not consume wasteful current when the operating temperature is low, and the capability of the boosted voltage output of the charge pump circuit when the operating temperature is high. It is an object of the present invention to provide a drive circuit for a charge pump circuit, which can prevent the voltage from decreasing.

[0013]

According to one aspect of the present invention, there is provided a driving circuit for a charge pump circuit for supplying a clock pulse for driving a charge pump circuit. A constant current source that generates a constant current having an oscillation circuit that generates a clock pulse having an oscillation frequency having a positive temperature coefficient corresponding to the constant current generated by the constant current source, and supplies the clock pulse to the charge pump circuit. , Is characterized by having.

In the drive circuit of the charge pump circuit having the above-described structure, the constant current source increases the amount of current in accordance with the temperature rise, that is, generates a constant current having a positive temperature coefficient, and has the positive temperature coefficient. The oscillation frequency of the oscillation circuit that generates a clock pulse to be supplied to the charge pump circuit by the constant current increases as the temperature increases, that is, is set so as to have a positive temperature coefficient.

Therefore, according to the first aspect of the present invention, the oscillation frequency of the oscillation circuit that supplies the clock pulse for driving the charge pump circuit has a positive temperature coefficient, so that the oscillation frequency is low when the operating temperature is low. In other words, the charge pump circuit is prevented from having an excessive charge pump capability, so that it is possible to prevent wasteful current consumption.

When the operating temperature is high, the oscillating frequency of the oscillation circuit increases as the temperature rises. Therefore, when the operating temperature is high, a decrease in the charge pump capability of the charge pump circuit can be compensated.

According to a second aspect of the present invention, there is provided a drive circuit for a charge pump circuit for supplying a clock pulse for driving a charge pump circuit, wherein a reference voltage having a positive temperature coefficient and an output of the charge pump circuit are provided. A constant current source that generates a constant current based on a difference voltage value from a voltage value obtained by dividing the voltage; and a clock pulse having an oscillation frequency having a positive temperature coefficient corresponding to the constant current generated by the constant current source. An oscillation circuit for supplying the charge pump circuit;
It is characterized by having.

In the drive circuit of the charge pump circuit having the above-described structure, the voltage value increases in accordance with the temperature rise by the constant current source, that is, the reference voltage value having a positive temperature coefficient and the output voltage of the charge pump circuit are divided. A constant current is generated by a difference voltage value from the compressed voltage value, and the oscillation frequency of an oscillation circuit that generates a clock pulse to be supplied to the charge pump circuit is increased by the constant current according to a rise in temperature.
That is, it is set to have a positive temperature coefficient.

According to the second aspect of the present invention, the oscillating frequency of the oscillating circuit that supplies the clock pulse for driving the charge pump circuit has a positive temperature coefficient, so that the oscillating frequency is low when the operating temperature is low, Since the charge pump capacity of the charge pump circuit is suppressed from being excessive, it is possible to prevent unnecessary consumption of current, and when the operating temperature is high, the oscillation frequency of the above-mentioned oscillation circuit increases with the temperature rise. , The charge pump capability of the charge pump circuit can be compensated for when the operating temperature is high.

Further, the amount of the constant current generated by the constant current source that determines the oscillation frequency of the oscillation circuit that supplies the clock pulse is divided by the output voltage of the charge pump circuit, that is, the negative feedback amount of the output voltage. , The fluctuation of the output voltage due to the load fluctuation of the charge pump circuit can be corrected.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a drive circuit of a charge pump circuit according to a first embodiment of the present invention.

The drive circuit of the charge pump circuit according to the present embodiment has a constant current source circuit as a constant current source that generates a constant current having a positive temperature coefficient, in which the amount of current increases as the temperature rises. 10 and a constant current generated by the constant current source circuit 10, the oscillation frequency increases as the temperature rises, that is, a clock pulse having an oscillation frequency having a positive temperature coefficient is generated, and the charge pump circuit 4
And an oscillating circuit 20 for supplying 0.

The charge pump driving clock circuit 30
Specifically, for example, as shown in FIG.
34 to 37, the NOR gates 32 and 33 are connected as shown in the figure, and two types of clocks Φ1 and Φ2 in which clock pulses of a constant frequency generated by the oscillating circuit 20 are not overlapped with each other in a high-level period. (FIG. 7
(See (B)) and outputs the same to the charge pump circuit 40.

The constant current source circuit 10 includes a reference voltage generating circuit 12 for generating a reference voltage having a positive temperature coefficient, that is, a reference voltage having a positive temperature coefficient, and an output voltage of the reference voltage generating circuit 12. An amplifier circuit 14 for amplifying the reference voltage Vref, and an output voltage of the amplifier circuit 14 as inputs,
It comprises a voltage-current conversion circuit 16 for converting this into a current.

The voltage-current conversion circuit 16 includes an operational amplifier 17,
The operational amplifier 17 has a non-inverting input terminal connected to the output terminal of the amplifier circuit 14, and an inverting input terminal connected to the other end of the resistor 18 having one end grounded. The output terminal of the operational amplifier 17 is connected to the gate of the NMOS transistor Q0.
The source of the OS transistor Q0 is connected to the inverting input terminal of the operational amplifier 17, and the drain is the PMO of the oscillation circuit 20.
It is connected to the drain of S transistor Q1.

Further, the oscillation circuit 20 includes an odd-numbered (three in this embodiment) inverter INV coupled in a ring shape.
1, INV2, INV3 and these inverters INV
, INV2, INV3 for driving PMOS transistors Q1-Q5 and NMOS transistors Q6-Q
9. PMOS transistors Q1 to Q1
Q5 has a source and a gate commonly connected to each other, and a power supply voltage VDD is supplied to the source. The sources and gates of the NMOS transistors Q6 to Q9 are commonly connected, and the source is grounded.

The drain of the PMOS transistor Q1 is connected to the drain of the NMOS transistor Q0 constituting the voltage-current conversion circuit 16, and the drain of the PMOS transistor Q2 is connected to the drain of the NMOS transistor Q6. The drain of the NMOS transistor Q6 is NMO
It is connected to the gate of the S transistor.

The drains of the PMOS transistors Q3 to Q5 are connected to the sources of the PMOS transistors of the CMOS inverter constituting the inverters INV1 to INV3, respectively.

The drains of the NMOS transistors Q7 to Q9 are connected to the CMs constituting the inverters INV1 to INV3.
It is connected to the source of the NMOS transistor of the OS inverter. Cn is a load capacity of the inverters INV1 to INV3.

Next, FIG. 3 shows a specific configuration of the reference voltage generating circuit 12, and FIG. 4 shows a specific configuration of the amplifier circuit. First, in FIG. 3, the reference voltage generation circuit 12 is a PMO
The sources and gates of the S transistors Q10, Q12, and Q14 are commonly connected, and the gate and drain of the PMOS transistor Q11 are short-circuited.

The drain of the NMOS transistor Q12 is connected to the drain of the PMOS transistor Q10, and the drain and gate of the NMOS transistor Q12 are short-circuited. The source of the NMOS transistor Q12 is connected to the anode of the diode D1, and the cathode of the diode D1 is grounded. The gate of the NMOS transistor Q12 is connected to the gate of the NMOS transistor Q13, the drain of the NMOS transistor Q13 is connected to the drain of the PMOS transistor Q11,
The source is connected to the anode of the diode D2 via the resistor 50. The cathode of the diode D2 is grounded. PMOS transistors Q10 and Q11, NM
The OS transistors Q12 and Q13 each constitute a current mirror circuit. The area ratio of the PN junction surfaces of the diodes D1 and D2 formed on the semiconductor substrate is 1: n.

Next, the configuration of the amplifier circuit 14 will be described. As shown in FIG.
And a reference voltage source 66 (reference voltage Vsg) having no temperature coefficient and connected to the inverting input terminals of the operational amplifier 60 and the resistors 62 and 64 for determining the amount of negative feedback via the resistor 64.
It is composed of The output voltage Vref of the reference voltage generating circuit 12 is input to the non-inverting input terminal of the operational amplifier 60, and the operational amplifier 60, that is, the amplifier circuit 14 outputs the voltage Vo.
ut1 is output.

The operation of the charge pump circuit driving circuit according to the first embodiment of the present invention having the above configuration will be described. First, in the reference voltage generating circuit shown in FIG.
PMOS transistor Q10, NMOS transistor Q
When the current I flows through the diode D1 through the
Since the OS transistors Q10 and Q11 and the NMOS transistors Q12 and Q13 each constitute a current mirror circuit, the current I also flows through the diode D2,
Further, since the gate-source voltages of the PMOS transistor Q11 and the PMOS transistor Q14 are equal, the resistance 52
The current I also flows. Therefore, the potential at the connection point between the source of the NMOS transistor Q12 and the diode D1 is VA, the potential at the connection point between the source of the NMOS transistor Q13 and the resistor 50 is VB, and the resistance values of the resistors 50 and 52 are R1, R2 and the diode D1, Assuming that the leakage current in the reverse direction of D2 is Is,

[0034]

VA = (kT / q) ln (I / Is) (4)

[0035]

VB = (kT / q) ln (I / nIs) + R1 · I (5) where k is Boltzmann's constant, T is absolute temperature, and q is the amount of electron charge.

Also,

[0037]

Since VA = VB (6), from the equations (4), (5) and (6),

[0038]

I = (kT / q) ln (n) / R1 (7) Therefore, the reference voltage Vref, which is the output voltage of the reference voltage generation circuit 12, is

[0039]

Vref = I · R2 = (R2 / R1) · ln (n) · (kT / q) (8) Here, since (R2 / R1) · ln (n) is a circuit constant independent of temperature, if these are K1,

[0040]

Vref = K1 · (kT / q) (9) Therefore, the reference voltage Vref rises as the temperature rises, so that the temperature coefficient dVref / dT of the reference voltage Vref is positive.

Next, the output Vout1 of the amplifier circuit 14 shown in FIG.

[0042]

Vout1 = (1 + R3 / R4) · Vref + (R3 / R4) · Vsg = (1 + R3 / R4) · K1 · (kT / q) + (R3 / R4) · Vsg (10) I can do it. As described above, Vsg is a reference voltage having no temperature coefficient, and determines the absolute value voltage of Vout1. Here, a circuit constant independent of temperature (1 + R3 /
If (R4) · K1 is K2 and (R3 / R4) · Vsg is V1, equation (10) becomes

[0043]

Vout1 = K2 · (kT / q) + V1 (11) Therefore, the output current I1 of the voltage-current conversion circuit 16 in FIG.

[0044]

I1 = Vout1 / R0 = K2 · (kT / q) / R0 + V1 / R0 (12) At this time, the output current I1 of the voltage / current conversion circuit 16
Can be represented by the differential value of the equation (12).
Therefore, assuming that the resistance Ro is externally connected to the IC and that the temperature fluctuation of the resistance value can be ignored, the temperature coefficient of the output current I1 of the voltage-current conversion circuit 16 becomes

[0045]

DI1 / dT = K2 · (k / q) / R0 (13) Therefore, the temperature coefficient of the output current I1 of the voltage-current conversion circuit 16 is positive and its value is R0, R1, R2, R3, R4.
Can be set freely.

On the other hand, the oscillation circuit 20 is connected to the inverter INV1.
PMOS transistors Q1 to Q5 driving .about.INV3
Since the current I generated by the voltage-current conversion circuit 16 flows through the PMOS transistor Q1 because the current mirror circuit is formed, the PMOS transistors Q1 to Q5
Since the gate and the source are connected in common, the voltages between the gate and the source of the PMOS transistors Q1 to Q5 become equal, the current I flows through the PMOS transistors Q1 to Q5, respectively, and the NMOS transistor Q7
Similarly, the currents I to Q9 are also converted from the inverters INV1 to INV1 to I9.
It operates to pull in via NV3. As a result, the load capacitance Cn of the inverters INV1 to INV3 is charged and discharged by the current I, and the inverters INV1 to INV3 are charged and discharged.
A clock pulse having a frequency f determined by the delay time of the input signal and the number of stages of the inverter is generated. Here, the number of stages of the inverter is N, and of the inverter delay time, the delay time when the output changes from low level to high level when the input changes from high level to low level is TPL,
TPHL is the delay time when the output changes from high level to low level when the input changes from low level to high level.
Then, the oscillation frequency f becomes

[0047]

F = 1 / (2N + 1) (TPLH + TPHL) (14) The amount of current increases as the temperature generated by the constant current source circuit 10 increases, that is, the constant current I1 having a positive temperature coefficient increases and is supplied to each of the inverters INV1, INV2, and INV3 in the oscillation circuit 20. When the current increases, the time required for charging and discharging the load capacitance Cn of the input node of the next-stage inverter connected subsequently is shortened, so that the oscillation frequency increases.

On the other hand, when the constant current I1 decreases and the current supplied to each of the inverters INV1, INV2, INV3 decreases, it is necessary to charge and discharge the load capacitance Cn of the input node of the next-stage inverter connected subsequently. The time increases and the oscillation frequency decreases. Therefore, the oscillation frequency f of the oscillation circuit 20 increases in proportion to the amount of the constant current I1 generated by the constant current source circuit 10.

The oscillation frequency f of the oscillation circuit 20 also includes the temperature characteristics of the inverters INV1, INV2 and INV3. The ON resistance Ron of the MOS transistor is MO
It is inversely proportional to the mobility u of the semiconductor forming the S transistor. Since the mobility u generally has a negative temperature coefficient, the ON resistance Ron of the MOS transistor has a positive temperature coefficient. Therefore, the oscillation frequency of the oscillation circuit requires the output resistances of the inverters INV1, INV2, and INV3 to increase as the operating temperature rises, and is required to charge and discharge the load capacitance of the input node of the next-stage inverter connected subsequently. The time increases, and the oscillation frequency f decreases.

Here, the inverter INV of the oscillation circuit 20
1. Oscillation frequency f due to temperature characteristics of INV2 and INV3
Is expressed as dF (INV) / dt, dI
The circuit constants of the constant current source circuit 10, such as 1 / dT> dF (INV) / dt,
2, 62, 64 resistance values R0, R1, R2, R3, R4
Is determined, the temperature fluctuation of the oscillation frequency f of the oscillation circuit 20 is determined by the temperature coefficient dF (INV) / dt because the temperature coefficient dI1 / dT of the constant current I1 is dominant. It becomes possible to set f to a positive temperature coefficient.

The output current allowable value I _LO of the charge pump circuit 40 can be increased by increasing the frequency of the clocks Φ1 and Φ2 output from the charge pump drive clock circuit 30 according to the equation (2). Therefore, it is possible to increase the output power Wout of the charge pump circuit 40 when the operating temperature is high.

According to the drive circuit of the charge pump circuit according to the first embodiment of the present invention, the oscillation circuit is driven by the constant current having the positive temperature coefficient generated by the constant current source circuit, so that the positive temperature A clock with an oscillating frequency with a coefficient is generated and the charge pump circuit is driven by that clock, so when the operating temperature is low, the oscillating frequency decreases and the charge pump circuit's charge pump capability is prevented from becoming excessive. Therefore, it is possible to prevent useless current consumption.

When the operating temperature is high, the oscillation frequency of the oscillation circuit increases as the temperature rises. Therefore, it is possible to compensate for a decrease in the charge pump capability of the charge pump circuit when the operating temperature is high.

Next, FIG. 5 shows a configuration of a drive circuit of a charge pump circuit according to a second embodiment of the present invention. The drive circuit according to the second embodiment differs from the drive circuit according to the first embodiment in configuration in that the constant current supplied to the oscillation circuit is different from the reference voltage having a positive temperature coefficient and the charge pump circuit. This is the point that the constant current source circuit is configured to generate the output voltage by the difference voltage value from the divided voltage value, and the other configuration is the same as that of the first embodiment. Are denoted by the same reference numerals, and overlapping description will be omitted.
In FIG. 5, the drive circuit of the charge pump circuit according to the second embodiment increases the reference voltage as the temperature rises, that is, the reference voltage having a positive temperature coefficient and the output voltage of the charge pump circuit 40. A constant current source circuit 10 'for generating a constant current based on a difference voltage value from the divided voltage value;
An oscillation circuit 20 that generates a clock pulse having an oscillation frequency having a positive temperature coefficient by the constant current generated by the constant current source circuit 10 ′ and supplies the clock pulse to the charge pump circuit 40. The output voltage Vou of the charge pump circuit 40
t is divided by the capacitors Ca and Cb, and the output voltage is applied to one end of the resistor R0 via the buffer amplifier 70 of the constant current source circuit 10 '.

In the above configuration, the charge pump circuit 40
Assuming that the voltage dividing ratio of the output voltage Vout (negative feedback rate of the output voltage Vout) is 1 / B, the divided voltage (negative feedback amount) of the output voltage Vout of the charge pump circuit 40, which is the voltage across the capacitor Cb, is ( 1 / B) · Vout, and the operational amplifier 17, buffer amplifier 70, NMOS transistor Q
0, the output current I1 of the voltage-current conversion circuit 16 'composed of the resistor R0 has a potential at one end of the resistor R0 of Vout1 and a potential at the other end of (1 / B) · Vout.

[0056]

## EQU15 ## I1 = (Vout1- (1 / B) .Vout) / Ro (15) As is apparent from the above equation (15), the voltage-current conversion circuit 16 'in the second embodiment is used.
Is different from the output current I1 of the voltage-current conversion circuit in the first embodiment, in that the output current I1 in the first embodiment depends only on Vout1 of the amplifier circuit 14, but the second In the embodiment, the output current I1 is Vo
That is, it depends not only on ut1, but also on (1 / B) · Vout. The divided voltage (1 / B) · Vout of the output voltage Vout of the charge pump circuit 40 functions so as to be negatively fed back. That is, when the output voltage Vout of the charge pump circuit 40 increases due to the load fluctuation and the operating temperature fluctuation of the charge pump circuit 40, the divided voltage (1 / B) ·
Vout also increases. At that time, the output current I1 of the voltage-current conversion circuit 16 ′ is reduced from the equation (15). Therefore, in that case, the oscillation frequency of the oscillation circuit 20 decreases, and the output power Wout of the charge pump circuit 40 operating with the clock pulse output from the oscillation circuit 20 can be reduced.

The value of the voltage division ratio 1 / B can be set by the ratio of the capacitors Ca and Cb in FIG. By setting the voltage division ratio 1 / B to an optimal value, output fluctuations due to output load fluctuations and operating temperature fluctuations of the charge pump circuit 40 can be corrected.

According to the drive circuit of the charge pump circuit according to the second embodiment of the present invention, the difference between the reference voltage value having a positive temperature coefficient and the voltage value obtained by dividing the output voltage of the charge pump circuit is obtained. Since the constant current is generated by the voltage value, the oscillation circuit is driven by the constant current with the constant current, a clock of the oscillation frequency having a positive temperature coefficient is generated, and the charge pump circuit is driven by the clock. ,
When the operating temperature is low, the oscillation frequency becomes low, and the charge pump capacity of the charge pump circuit is prevented from becoming excessive, so that unnecessary current consumption can be prevented. Since the oscillation frequency of the oscillation circuit increases as the temperature rises, it is possible to compensate for a decrease in the charge pump capability of the charge pump circuit when the operating temperature is high.

Further, the amount of the constant current generated by the constant current source that determines the oscillation frequency of the oscillation circuit that supplies the clock pulse is divided by the voltage value obtained by dividing the output voltage of the charge pump circuit, that is, the negative feedback amount of the output voltage. , The fluctuation of the output voltage due to the load fluctuation of the charge pump circuit can be corrected.

[0060]

According to the first aspect of the present invention, since the oscillation frequency of the oscillation circuit that supplies the clock pulse for driving the charge pump circuit has a positive temperature coefficient, the oscillation frequency is low when the operating temperature is low. In other words, the charge pump circuit is prevented from having an excessive charge pump capability, so that it is possible to prevent wasteful current consumption.

When the operating temperature is high, the oscillating frequency of the oscillation circuit increases as the temperature rises. Therefore, it is possible to compensate for a decrease in the charge pump capability of the charge pump circuit when the operating temperature is high.

According to the second aspect of the present invention, the oscillating frequency of the oscillating circuit that supplies the clock pulse for driving the charge pump circuit has a positive temperature coefficient, so that the oscillating frequency is low when the operating temperature is low, Since the charge pump capacity of the charge pump circuit is suppressed from being excessive, it is possible to prevent unnecessary consumption of current, and when the operating temperature is high, the oscillation frequency of the above-mentioned oscillation circuit increases with the temperature rise. , The charge pump capability of the charge pump circuit can be compensated for when the operating temperature is high.

Further, the amount of constant current generated by the constant current source that determines the oscillation frequency of the oscillation circuit that supplies the clock pulse is divided by the voltage value obtained by dividing the output voltage of the charge pump circuit, that is, the negative feedback amount of the output voltage. , The fluctuation of the output voltage due to the load fluctuation of the charge pump circuit can be corrected.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a drive circuit of a charge pump circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a specific configuration of a charge pump drive clock circuit in FIG. 1;

FIG. 3 is a circuit diagram showing a specific configuration of a reference voltage generation circuit in FIG. 1;

FIG. 4 is a circuit diagram showing a specific configuration of the amplifier circuit in FIG. 1;

FIG. 5 is a circuit diagram showing a configuration of a drive circuit of a charge pump circuit according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram showing a configuration of a conventional general charge pump circuit.

FIG. 7 is a time chart showing an operation state of the charge pump circuit shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Constant current source circuit 12 Reference voltage generation circuit 14 Amplification circuit 16 Voltage current conversion circuit 20 Oscillation circuit 30 Charge pump drive clock circuit 40 Charge pump circuit 70 Buffer amplifier 100 Input terminal 200 Output terminal

Claims (2)

[Claims] 1. A drive circuit for a charge pump circuit for supplying a clock pulse for driving a charge pump circuit, comprising: a constant current source for generating a constant current having a positive temperature coefficient; and a constant current source generated by the constant current source. An oscillation circuit that generates a clock pulse having an oscillation frequency having a positive temperature coefficient according to a constant current and supplies the clock pulse to the charge pump circuit. 2. A charge pump circuit driving circuit for supplying a clock pulse for driving a charge pump circuit, comprising: a reference voltage value having a positive temperature coefficient; a voltage value obtained by dividing an output voltage of the charge pump circuit; A constant current source that generates a constant current according to the difference voltage value of the constant current source; a clock pulse having an oscillation frequency having a positive temperature coefficient corresponding to the constant current generated by the constant current source; and supplying the clock pulse to the charge pump circuit. A driving circuit for a charge pump circuit, comprising: an oscillation circuit.