TWI392207B - A dc/dc conversion device, a frequency skip module and a method of frequency skip control - Google Patents

Description

DC/DC conversion device, frequency hopping control module and frequency hopping control method

The invention relates to a voltage conversion control method, in particular to a frequency hopping control method for a voltage conversion circuit operating in a frequency hopping mode.

Referring to FIG. 1 , a conventional DC/DC converter 900 includes a DC/DC converter 901 and a feedback control circuit 902. The DC/DC converter 901 is a half bridge LLC oscillator circuit. And feedback control circuit 902 has an ST L6599 type control chip 903.

When the load current is reduced (increased load resistance Ro), DC / DC converter output voltage Vo 901 will slightly increase, causing feedback voltage V _comp at point A control circuit 902 is decreased, point A when the voltage V _comp When the preset value of the control chip 903 is lower, the feedback control circuit 902 will not output the driving signals HVG, LVG, so that the DC/DC converter 901 stops the voltage conversion operation, and at this time, the DC/DC converter 901 stops working. An interval of time. Since the output voltage Vo of the DC/DC converter 901 drops slightly during the intermittent time, the voltage V _comp at the point A in the feedback control circuit 902 rises. Therefore, the feedback control circuit outputs the drive signal HVG, The LVG causes the DC/DC converter 901 to start a voltage conversion operation and enter the operating time.

Therefore, the conventional feedback control circuit 902 controls whether the DC/DC converter 901 operates or is intermittent according to the change in the voltage V _comp of the point A. Referring to FIG. 2, the voltage V _comp at point A is a gradual signal, that is, the time at which the point V voltage V _{comp is} decremented to the preset value of the control wafer 903 is slower than the output voltage Vo, so that the DC/DC is slow. The converter 901 generates an excessively long working time during the decrementing of the voltage V _comp at point A, as shown by time t91-t92 of FIG. However, the energy converted by the DC/DC converter 901 is mostly concentrated in the first few cycles, as shown by the inductor current Ipri in FIG. 2, and the energy converted by the DC/DC converter 901 in the last few cycles is little or even almost The energy is converted, so that an excessively long working time will cause power loss of the conventional DC/DC converter 900.

Accordingly, it is an object of the present invention to provide a frequency hopping control method that can reduce power consumption.

Therefore, the frequency hopping control method of the present invention is applied to a frequency hopping control module, and the frequency hopping control module is suitable for use with a voltage conversion circuit for generating a voltage conversion circuit operating in a frequency hopping mode. The driving signal of the driving voltage conversion circuit, the frequency hopping control method comprises the following steps:

(A) generating a periodic pulse signal;

(B) generating a control signal according to an adjustment signal inversely proportional to the output voltage of the voltage conversion circuit, each cycle of the control signal having an off-time and a fixed on-time. And the intermittent time is inversely proportional to the adjustment signal; and

(C) generating a driving signal according to the control signal and the pulse signal to drive the voltage conversion circuit for voltage conversion.

Preferably, in step (B), the output current of a voltage controlled current source is controlled by the adjustment signal, and the output current is charged to a first threshold voltage value to determine the intermittent time.

Preferably, the working time of step (B) is the time during which the storage capacitor discharges a resistor to a second threshold voltage value lower than the first threshold voltage value.

Preferably, the step (C) is to "AND" the control signal and the pulse signal to generate a driving signal.

Furthermore, it is an object of the present invention to provide a frequency hopping control module that can reduce power consumption.

The frequency hopping control module of the present invention is suitable for use with a voltage conversion circuit for generating a driving signal of a driving voltage conversion circuit when the voltage conversion circuit operates in a frequency hopping mode, and the frequency hopping control module comprises: a high frequency A signal generator, an intermittent time adjuster and a drive signal generating circuit.

The high frequency signal generator is configured to generate a periodic pulse signal; the intermittent time adjuster generates a control signal according to an adjustment signal inversely proportional to the output voltage of the voltage conversion circuit, and each cycle of the control signal has an intermittent time and a The fixed working time, and the intermittent time is inversely proportional to the adjustment signal; the driving signal generating circuit generates a driving signal according to the pulse signal and the control signal to drive the voltage conversion circuit to perform voltage conversion.

Preferably, the intermittent time adjuster comprises a voltage controlled current source, a storage capacitor and a hysteresis comparator. The voltage-controlled current source generates an output current according to the output voltage of the voltage conversion circuit; the storage capacitor has a first end coupled to the voltage-controlled current source and a grounded second end; the hysteresis comparator has a coupled storage capacitor The non-inverting terminal of the first end, the inverting terminal receiving a reference voltage, and an output terminal, the hysteresis comparator forms a hysteresis interval by the reference voltage, and the hysteresis interval has a first threshold voltage value. The hysteresis comparator limits the voltage-controlled current source to charge the storage capacitor to a first threshold voltage to determine the interval time, and the output of the hysteresis comparator outputs a control signal.

Further, the intermittent time adjuster further includes a resistor having a first end coupled to the storage capacitor and a second end connected to the ground, and the hysteresis interval further has a second threshold lower than the first threshold voltage Voltage value. The hysteresis comparator limits the storage capacitor to discharge the resistor to a second threshold voltage to determine the operating time.

Further, the intermittent time adjuster further includes a first switch, a second switch, and an inverter. The first switch is connected in series between the voltage controlled current source and the storage capacitor; the second switch is connected in series between the resistor and the ground; the input end of the inverter is coupled to the output of the hysteresis comparator, and the output of the inverter The first switch is controlled to open and close, the output of the hysteresis comparator controls the opening and closing of the second switch, and the first switch and the second switch are used to switch the charging/discharging of the storage capacitor.

Further, it is an object of the present invention to provide a DC/DC converter which can reduce power consumption.

The DC/DC converter of the present invention comprises a voltage conversion circuit and a frequency hopping control module. The voltage conversion circuit operates in a frequency hopping mode; the frequency hopping control module comprises a high frequency signal generator, an intermittent time adjuster and a driving signal generating circuit, the internal components of which are the same as described above.

The function of the invention is that the frequency hopping control module adjusts the intermittent time of the control signal according to the output voltage of the voltage conversion circuit, and fixes the working time of the control signal, so that the problem that the working time is too long can be avoided.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 3, a DC/DC conversion device 100 of the present invention is applied to a Frequency-to-Hopping Spread Spectrum (FHSS) and is applied at a fixed working time (Frequency-Hopping Spread Spectrum (FHSS)). Under on-time, the length of the off-time is appropriately adjusted so that the DC/DC converter 100 transmits energy efficiently during the operating time and reduces the loss of the circuit at the time of light load. In the present embodiment, the DC/DC converter device 100 includes a voltage conversion circuit 1 and a frequency hopping control module 2.

The voltage conversion circuit 1 can be applied to isolated and non-isolated DC/DC converters such as Buck Converter, Boost Converter, Buck-Boost Converter. a flyback converter, a forward converter, an LLC oscillator circuit, etc., and the voltage conversion circuit 1 of the embodiment is a half bridge LLC oscillation circuit and has a first power Switch Q1 and second power switch Q2.

The frequency hopping control module 2 is configured to generate a set of driving signals to control the opening and closing of the first power switch Q1 and the second power switch Q2 in the voltage converting circuit 1. However, in the present embodiment, the voltage conversion circuit 1 is operated in a frequency hopping mode. In the frequency hopping mode, the frequency hopping control module 2 controls the voltage conversion circuit 1 to alternately operate between an operation time and an intermittent time. During the working time, the frequency hopping control module 2 outputs a driving signal, so that the voltage converting circuit 1 performs voltage conversion; otherwise, the frequency hopping control module 2 opens (open/off) the first power switch Q1 and the intermittent time. The second power switch Q2 is actuated by the stop voltage conversion circuit 1. The frequency hopping control module 2 includes a feedback adjustment circuit 3, a high frequency signal generator 4, an intermittent time adjuster 5, and a drive signal generating circuit 6.

The feedback adjustment circuit 3 is configured to generate an adjustment signal Vreg according to the output voltage Vo of the voltage conversion circuit 1. The adjustment signal Vreg is used to generate the control signal LF and control the switching frequency of the driving signal generated by the driving signal generating circuit 6, and the feedback adjustment circuit is provided. 3, the generated adjustment signal Vreg is transmitted to the high frequency signal generator 4 and the intermittent time adjuster 5; the high frequency signal generator 4 and the intermittent time adjuster 5 respectively generate a set of periodic pulse signals Drv01, Drv02 according to the adjustment signal Vreg And a control signal LF, the detailed operation of which is further described; the driving signal generating circuit 6 generates a driving signal sufficient to drive the first power switch Q1 and the second power switch Q2 to be turned on and off according to the pulse signals Drv01, Drv02 and the control signal LF. Drv1, Drv2.

In particular, when the load current is smaller (the load resistance Ro is larger), the output voltage Vo of the voltage conversion circuit 1 rises slightly, and therefore, the first power switch Q1 and the second power switch Q2 need to be higher. The switching frequency is maintained to maintain a fixed output voltage Vo, so a lower voltage value adjustment signal Vreg is required, in other words, the output voltage Vo is inversely proportional to the adjustment signal Vreg.

Referring to FIG. 4, an internal circuit diagram of the intermittent time adjuster 5 of the present embodiment includes a voltage controlled current source 51, a first switch S1, a second switch S2, and a storage capacitor C1. A resistor R1, an inverter 52 and a hysteresis comparator 53.

The voltage-controlled current source 51 is configured to change the charging current of the output according to the adjustment signal Vreg; the first switch S1 has a first end 501 coupled to the voltage-controlled current source 51 and a second end 502; the storage capacitor C1 has a coupling The first end 503 of the second end 502 of the first switch S1 and the grounded second end 504 are connected to the second end 504 of the first switch S1. The resistor R1 has a first end 505 coupled to the first end 503 of the storage capacitor C1 and a second end 506. The second switch S2 has a first end 507 coupled to the second end 506 of the resistor R1 and a grounded second end 508. The hysteresis comparator 53 has a non-reverse coupled to the first end 503 of the storage capacitor C1. The phase end receives an inverting end of a reference voltage Vref and an output end; the input end of the inverter 52 is coupled to the output end of the hysteresis comparator 53, and the output end of the inverter 52 controls the first switch S1 and the The opening and closing of the two switches S2.

It is worth mentioning that the hysteresis comparator 53 forms a hysteresis using the reference voltage Vref. Referring to FIG. 5, it has a first threshold voltage value V _H and a second threshold voltage value V _L . In addition, the signal outputted by the output of the hysteresis comparator 53 is the control signal LF.

Referring to FIG. 6, first, it is assumed that the control signal LF is at a low level, so that the first switch S1 is closed (close/on), the second switch S2 is open (open/off), and the initial voltage of the storage capacitor C1 is Vc is zero. Therefore, the voltage-controlled current source 51 generates a corresponding charging current after receiving the adjustment signal Vreg, and charges the storage capacitor C1 (eg, t0-t1 time), and when the voltage Vc stored in the storage capacitor C1 reaches the hysteresis comparator When the first threshold voltage value L1 (V _H ) of 53 is reached, the control signal LF is converted to a high level, so that the first switch S1 is turned on (open/off) to stop charging.

Specifically, the control signal LF includes the working time and the intermittent time, and the time when the storage capacitor C1 is charged to the first threshold voltage value L1 (V _H ) is the intermittent time in the control signal LF. At this time, the control signal LF is a low level. In other words, the driving signal generating circuit 6 generates an intermittent time and a working time in the driving signals Drv1 and Drv2 generated according to the control signal LF conversion, and the voltage converting circuit 1 temporarily stops the operation during the intermittent time until the working time is entered.

When the control signal LF is converted to the high level, the first switch S1 is turned on (open/off) and the second switch S2 is turned off (close/on), and the storage capacitor C1 starts to discharge the resistor R1 (eg, t1-t2 time). And the discharge time is the RC time constant. During the discharge, the voltage Vc of the storage capacitor C1 drops until it is lower than the second threshold voltage L2 (V _L ) of the hysteresis comparator 53, and the control signal LF is again converted to the low level.

In this embodiment, the time during which the storage capacitor C1 is discharged to the second threshold voltage value L2 (V _L ) is the operating time in the control signal LF. At this time, the control signal LF is at a high level. Since the capacitance of the storage capacitor C1 and the resistance of the resistor R1 are unchanged, the discharge time of the storage capacitor C1 will be fixed to the RC time constant, that is, the operating time of the control signal LF will be a fixed value. In other words, the time t1-t2 will be the same as the time t3-t4. Whether the time t0-t1 will be the same as the time t2-t3 is determined by the adjustment signal Vreg. If the adjustment signal Vreg is smaller, the storage capacitor C1 is The slower the voltage Vc is charged to the first threshold voltage value L1 (V _H ), so the interval time of the control signal LF is longer (such as t0-t1 time); conversely, the larger the adjustment signal Vreg is, the voltage Vc of the storage capacitor C1 is. The faster the charge is to the first threshold voltage value L1 (V _H ), the shorter the pause time of the control signal LF (e.g., t2-t3 time).

In general, in the case where the load current is reduced (the load resistance Ro is increased), the output voltage Vo of the voltage conversion circuit 1 rises, the voltage of the adjustment signal Vreg is lowered (the two are inversely proportional), so that the voltage-controlled current source 51 outputting a smaller charging current, the charging time becomes longer, so that the intermittent time in the control signal LF becomes longer, and the time during which the voltage conversion circuit 1 does not operate is relatively longer, so that the output voltage Vo decreases; conversely, when the voltage conversion circuit When the output voltage Vo of 1 decreases, the voltage of the adjustment signal Vreg rises, so that the voltage control current source 51 can charge the storage capacitor C1 with a larger charging current, so the intermittent time in the control signal LF is shortened, but the working time is fixed. Therefore, in one waveform period, the operating time of the voltage conversion circuit 1 for voltage conversion is relatively long, and the output voltage Vo is increased. Thus, the frequency hopping control module 2 can maintain the voltage conversion circuit 1 to output a fixed output voltage Vo. .

Referring to FIG. 3, FIG. 7 and FIG. 8, the detailed operation of the frequency hopping control module 2 will be described in detail below. FIG. 7 is a flowchart of the frequency hopping control method of the embodiment, and FIG. 8 is generated by the frequency hopping control module 2. Signal waveform diagram.

In step 10, the feedback adjustment circuit 3 generates an adjustment signal Vreg which is inversely proportional to the output voltage Vo according to the output voltage Vo of the voltage conversion circuit 1, and transmits the adjustment signal Vreg to the high frequency signal generator 4 and the intermittent time adjuster 5.

In step 20, the high frequency signal generator 4 generates a set of periodic pulse signals Drv01 and Drv02 according to the adjustment signal Vreg. The pulse signals Drv01 and Drv02 are respectively used to provide the driving signal generating circuit 6 to generate the driving signals Drv1 and Drv2.

While the high frequency signal generator 4 performs step 20, the intermittent time adjuster 5 performs steps 30 and 40 after receiving the adjustment signal Vreg.

In step 30, the intermittent time adjuster 5 controls the output current of the voltage-controlled current source 51 by using the adjustment signal Vreg, and charges the storage capacitor C1 to generate an intermittent time in the control signal LF, that is, t20-t30 time. As can be seen from FIG. 8, in the time interval t20-t30, the slope of the rising signal Vreg rises slowly, that is, the charging speed of the storage capacitor C1 is slow, so the intermittent time is longer; relatively, t40-t50 in the next cycle. In the time interval, the slope of the rising signal Vreg rises steeply. Therefore, the storage capacitor C1 is charged to the first threshold voltage faster, so the intermittent time is shorter.

In step 40, the intermittent time adjuster 5 generates the operating time in the control signal LF by using the RC time constant of the storage capacitor C1 to discharge the resistor R1 and the hysteresis interval of the hysteresis comparator 53, that is, t10-t20 time. In this embodiment, the length of the working time is three pulse periods of the pulse signal Drv01 (or Drv02). In other words, the capacitance of the storage capacitor C1 and the resistance of the resistor R need to be properly designed so that the RC time constant Three pulse periods for the pulse signal Drv01 (or Drv02).

In step 50, the driving signal generating circuit 6 converts the pulse signal Drv01 (or Drv02) and the control signal LF to generate driving signals Drv1 and Drv2 sufficient to drive the first power switch Q1 and the second power switch Q2. In the present embodiment, the driving signal generating circuit 6 is a digital logic circuit in which the pulse signals Drv01, Drv02 and the control signal LF are ANDed together to generate the driving signals Drv1 and Drv2.

Therefore, the driving signals Drv1 and Drv2 generated by the driving signal generating circuit 6 control the opening and closing of the first power switch Q1 and the second power switch Q2, so that the energy storage inductor Lr in the voltage converting circuit performs energy storage and energy release. Electricity The waveform of the sense current Ipri is as shown in FIG.

In addition, the length of the working time in the control signal LF is not limited to the period of the three pulse signals Drv01 (or Drv02), and the designer can change according to different requirements, as long as the resistance of the resistor R1 and the storage capacitor are properly adjusted. The capacitance value of C1 or the hysteresis interval of the hysteresis comparator 53 can be used. As mentioned in the following, when the frequency hopping control module 2 operates, only the length of the intermittent time is adjusted, so once the working time is determined, it will not change when the frequency hopping control module 2 operates.

In summary, the DC/DC converter device 100 of the present invention generates a drive signal Drv1 and Drv2 with fixed working time but adjustable intermittent time by the frequency hopping control module 2, which can maintain a fixed output voltage Vo and voltage. The conversion circuit 1 performs conversion in a pre-planned working time to avoid switching switching loss and poor voltage conversion performance caused by excessive working time.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

10~50‧‧‧Steps

100‧‧‧DC/DC converter

1‧‧‧Voltage conversion circuit

2‧‧‧Frequency hopping control module

3‧‧‧ feedback adjustment circuit

4‧‧‧High frequency signal generator

5‧‧‧Intermittent time regulator

501‧‧‧ first end (first switch)

502‧‧‧ second end (first switch)

503‧‧‧First end (storage capacitor)

504‧‧‧second end (storage capacitor)

505‧‧‧ first end (resistance)

506‧‧‧second end (resistance)

507‧‧‧ first end (second switch)

508‧‧‧second end (second switch)

51‧‧‧voltage controlled current source

52‧‧‧Inverter

53‧‧‧hysteresis comparator

6‧‧‧Drive signal generation circuit

Q1‧‧‧First power switch

Q2‧‧‧second power switch

Vo‧‧‧ output voltage

LF‧‧‧ control signal

Vreg‧‧‧ adjustment signal

Vc‧‧‧ voltage

V _H ‧‧‧first threshold voltage value

V _L ‧‧‧second threshold voltage value

Drv01‧‧‧ pulse signal

Drv02‧‧‧ pulse signal

Drv1‧‧‧ drive signal

Drv2‧‧‧ drive signal

S1‧‧‧ first switch

S2‧‧‧ second switch

C1‧‧‧ storage capacitor

R1‧‧‧ resistance

Ro‧‧‧ load resistor

Lr‧‧‧ storage inductor

1 is a circuit diagram showing the internal component relationship of a conventional DC/DC converter; FIG. 2 is a waveform diagram illustrating the problem of energy loss caused by a conventional DC/DC converter because the working time is too long; FIG. 3 is a circuit diagram. , illustrating the comparison of the DC/DC converter of the present invention FIG. 4 is a circuit diagram illustrating the internal circuit of the intermittent time adjuster of the present embodiment; FIG. 5 is a waveform diagram illustrating the hysteresis interval of the hysteresis comparator of the present embodiment; FIG. 6 is a waveform diagram illustrating How does the intermittent time adjuster generate the control signal LF; FIG. 7 is a flow chart illustrating the detailed flow of the frequency hopping control method of the present invention; and FIG. 8 is a waveform diagram illustrating how the frequency hopping control module generates the drive signals Drv1 and Drv2.

100. . . DC/DC converter

1. . . Voltage conversion circuit

2. . . Frequency hopping control module

3. . . Feedback adjustment circuit

4. . . High frequency signal generator

5. . . Intermittent time regulator

6. . . Drive signal generation circuit

Claims (20)

A frequency hopping control method is applied to a frequency hopping control module, and the frequency hopping control module is suitable for use with a voltage conversion circuit for generating a driving voltage conversion when the voltage conversion circuit operates in a frequency hopping mode The driving signal of the circuit, the frequency hopping control method comprises the following steps: (A) generating a periodic pulse signal; (B) generating a control signal according to an adjustment signal inversely proportional to the output voltage, each of the control signals The cycle includes an intermittent time and a fixed working time, and the intermittent time is inversely proportional to the adjustment signal; and (C) generating the driving signal according to the control signal and the pulse signal to drive the voltage conversion circuit to perform voltage conversion. The frequency hopping control method according to claim 1, wherein the step (A) is to generate a periodic pulse signal, the frequency of the pulse signal being the highest allowable switching frequency. According to the frequency hopping control method of claim 1, wherein the step (B) is to control the output current of a voltage control current source by using the adjustment signal, and charge the output current to a storage capacitor. The first threshold voltage value determines the intermittent time. The frequency hopping control method according to claim 3, wherein the working time of the step (B) is that the storage capacitor discharges a resistor to a second threshold voltage lower than the first threshold voltage. time. According to the frequency hopping control method of claim 1, wherein the step (C) is to "AND" the control signal and the pulse signal to generate the driving signal. A frequency hopping control module is suitable for use with a voltage conversion circuit for generating a driving signal for driving the voltage conversion circuit when the voltage conversion circuit operates in a frequency hopping mode, the frequency hopping control module includes: a high frequency signal generator for generating a periodic pulse signal; an intermittent time adjuster for generating a control signal according to an adjustment signal inversely proportional to the output voltage, each cycle of the control signal including an intermittent time and a fixed working time, and the intermittent time is inversely proportional to the adjustment signal; and a driving signal generating circuit generates the driving signal according to the pulse signal and the control signal to drive the voltage conversion circuit to perform voltage conversion. The frequency hopping control module according to claim 6, wherein the intermittent time adjuster comprises a voltage controlled current source, a storage capacitor and a hysteresis comparator, and the voltage control current source is according to the adjustment signal. An output current is generated, the storage capacitor has a first end coupled to the voltage-controlled current source and a grounded second end, the hysteresis comparator having a non-inverting end coupled to the first end of the storage capacitor, Receiving an inverting terminal and an output terminal of a reference voltage, the hysteresis comparator forming a hysteresis interval according to the reference voltage, the hysteresis interval having a first threshold voltage value, the hysteresis comparator limiting the voltage control current source to the The storage capacitor is charged to the first threshold voltage to determine the intermittent time, and the control signal is outputted by the output of the hysteresis comparator. The frequency hopping control module of claim 7, wherein the intermittent time adjuster further includes a resistor having a first end coupled to the storage capacitor and a grounded second end The hysteresis interval further has a second threshold voltage value lower than the first threshold voltage value, and the hysteresis comparator limits the storage capacitor to discharge the resistor to the second threshold voltage value to determine the working time. The frequency hopping control module according to claim 8 , wherein the intermittent time adjuster further comprises a first switch, a second switch and an inverter, wherein the first switch is connected in series with the voltage control Between the current source and the storage capacitor, the second switch is connected in series between the resistor and the ground, and the input end of the inverter is coupled to the output of the hysteresis comparator, and the output of the inverter controls the The first switch is turned on and off, the output of the hysteresis comparator controls the opening and closing of the second switch, and the first switch and the second switch are used to switch the charging/discharging of the storage capacitor. The frequency hopping control module according to claim 6 further includes a feedback adjustment circuit for generating the adjustment signal according to an output voltage of the voltage conversion circuit. The frequency hopping control module according to claim 6, wherein the high frequency signal generator generates a periodic pulse signal whose frequency is the highest allowable switching frequency. According to the frequency hopping control module of claim 6, wherein the driving signal generating circuit performs an AND operation on the control signal and the pulse signal to generate the driving signal. A DC/DC conversion device comprising: a voltage conversion circuit operating in a frequency hopping mode; and a frequency hopping control module comprising a high frequency signal generator, an intermittent time adjuster and a driving signal generating circuit, The high frequency signal generator is configured to generate a periodic pulse signal, and the intermittent time adjuster generates a control signal according to an adjustment signal inversely proportional to the output voltage, and each cycle of the control signal includes an intermittent time and a fixed time. The driving time is inversely proportional to the adjustment signal, and the driving signal generating circuit generates the driving signal according to the pulse signal and the control signal to drive the voltage conversion circuit to perform voltage conversion. The DC/DC converter of claim 13, wherein the intermittent time regulator comprises a voltage-controlled current source, a storage capacitor and a hysteresis comparator, and the voltage-controlled current source is based on the adjustment signal. An output current is generated, the storage capacitor has a first end coupled to the voltage-controlled current source and a grounded second end, the hysteresis comparator having a non-inverting end coupled to the first end of the storage capacitor, Receiving an inverting terminal and an output terminal of a reference voltage, the hysteresis comparator forming a hysteresis interval according to the reference voltage, the hysteresis interval having a first threshold voltage value, the hysteresis comparator limiting the voltage control current source to the The storage capacitor is charged to the first threshold voltage to determine the intermittent time, and the control signal is outputted by the output of the hysteresis comparator. The DC/DC converter of claim 14, wherein the intermittent time adjuster further includes a resistor having a first end coupled to the storage capacitor and a second end connected to the ground. The hysteresis interval further has a second threshold voltage value lower than the first threshold voltage value, and the hysteresis comparator limits the storage capacitor to discharge the resistor to the second threshold voltage value to determine the working time. The DC/DC converter of claim 15, wherein the intermittent time adjuster further includes a first switch, a second switch, and an inverter, wherein the first switch is connected in series with the voltage control Between the current source and the storage capacitor, the second switch is connected in series between the resistor and the ground, and the input end of the inverter is coupled to the output of the hysteresis comparator, and the output of the inverter controls the The first switch is turned on and off, the output of the hysteresis comparator controls the opening and closing of the second switch, and the first switch and the second switch are used to switch the charging/discharging of the storage capacitor. The DC/DC converter of claim 13, wherein the frequency hopping control module further comprises a feedback adjustment circuit for generating the adjustment signal according to an output voltage of the voltage conversion circuit. The DC/DC converter of claim 13, wherein the high frequency signal generator generates a periodic pulse signal, the frequency of the pulse signal being the highest allowable switching frequency. The DC/DC converter of claim 13, wherein the driving signal generating circuit generates the driving signal by performing a AND operation on the control signal and the pulse signal. The DC/DC converter of claim 13, wherein the voltage conversion circuit is a half bridge LLC oscillation circuit.