CN102468746A - Method for applying single-supply error amplifier to negative high voltage power control circuit - Google Patents

Abstract

The invention relates to a method for applying a single-supply error amplifier to a negative high voltage power control circuit. According to the application method, the sampling of the negative output voltage of a high voltage power supply by the common positive and negative double-supply error amplifier is broke through, and the sampling, phase reversal, comparative amplification and control adjustment of the output voltage of the negative high voltage power supply are realized through the single-supply error amplifier. The functional block diagram of the application method is shown as a figure in the specifications. The processing flow comprises the following steps of: sampling the output voltage of the negative high voltage power supply by using a resistor to obtain a negative low voltage signal; performing phase reversal on the sampled negative low voltage signal by using the single-supply error amplifier to obtain a positive low voltage signal; and transmitting the positive low voltage signal to single-supply error amplifier, comparing the positive low voltage signal with reference voltage, amplifying the positive low voltage signal, and outputting an error signal. The error signal can change the duty ratio of a power drive control signal, so that the final output voltage of the power supply is adjusted; and the method has a wide application prospect in the field of power supplies.

Description

The application process of single supply error amplifier in the negative high voltage power source control circuit

Technical field

The invention belongs to the special power supply technology, adopt the single power supply error amplifier to realize the sampling of negative high voltage power source output voltage, anti-phase, relatively amplify and control adjustment.

Background technology

In the electric vacuum tube transmitter, for the power supply of electric vacuum tube power supply is negative high voltage power source mostly, like cathode power of grid-control tube slow wave line power supply, cloudy keyholed back plate or the like.The high voltage source of, negative output high-power for this type is considered factors such as volume, weight and efficient, all adopts the pattern of Switching Power Supply usually.

In the Switching Power Supply; Through output voltage is sampled, sampled result feeds back to control circuit, and control circuit compares it and reference voltage; Obtain error voltage signal and control ratio switching time (duty ratio) of high frequency power switch element, thereby reach the purpose of adjusting output voltage.The comparison of sampled voltage and reference voltage, most of use error amplifiers are realized.

For the negative output high voltage source; Common way is: with resistance output voltage is sampled; Obtain a negative low voltage signal and deliver in the error amplifier, directly relatively amplify back generated error voltage signal with negative reference voltage, error amplifier must adopt positive and negative dual power supply; Both increased by one tunnel negative low-voltage power supply, and made the peripheral circuit of error amplifier become complicated again.

Thinking of the present invention is to utilize the single power supply error amplifier, realizes the sampling of negative high voltage power source output voltage, anti-phase, relatively amplifies and controls adjustment, has reduced the low-voltage power supply kind, makes Drive and Control Circuit simple, reliable simultaneously.

Summary of the invention

Content of the present invention provides the application process of a kind of single supply error amplifier in the negative high voltage power source control circuit.At first, the negative high voltage power source output voltage is sampled, obtain a negative low voltage signal with resistance; Then, the negative low voltage signal anti-phase that the error amplifier through single power supply will sample obtains positive low voltage signal; At last, after positive low-voltage sampled signal is sent in the single supply error amplifier and compares and enlarges with reference voltage, output error signal, this signal can change the duty ratio of power drives control signal, thereby realizes the adjustment of the final output voltage of power supply.

The present invention compared with prior art, its remarkable advantage is: single power supply, use components and parts few, have good operability, have the characteristics that real-time is good, detect good stability simultaneously, have highly application value in field of power supplies.

Below in conjunction with accompanying drawing technical solution of the present invention is described in detail.

Description of drawings

Fig. 1 is the workflow diagram of the application process of single supply error amplifier in the negative high voltage power source control circuit.

Fig. 2 is the circuit theory diagrams of the application process of single supply error amplifier in the negative high voltage power source control circuit.

Embodiment

The application process practical implementation step of single supply error amplifier of the present invention in the negative high voltage power source control circuit is referring to Fig. 1:

1. the output negative high voltage is carried out resistance sampling, convert negative low voltage signal to;

2. the single supply error amplifier carries out anti-phase to negative low voltage signal, produces the identical positive voltage feedback signal of amplitude;

3. positive voltage feedback signal and reference voltage relatively amplify through the single supply error amplifier, produce error signal;

4. change the duty ratio of drive control signal with error signal, reach the purpose of adjustment negative high voltage output.

The application process circuit theory diagrams of single supply error amplifier of the present invention in the negative high voltage power source control circuit are referring to Fig. 2:

1. R1, R2, Rn are sampling resistor, will export the negative high voltage conversion of signals and become low voltage signal.C1 is a filter capacitor, and ripple that both can the elimination sampled voltage also can guarantee the stability of whole power control system.

2. the N1A negative low-voltage that will sample is carried out anti-phase.The model of N1 is LM124, and its inside has No. 4 error amplifiers, and this error amplifier has open loop multiplication factor height, characteristics such as input impedance is high, output impedance is low, temperature drift is little, reliability height.Can be operated in the form of dual power supply or single power supply, adopt single power supply here.N1A is a road error amplifier wherein, is operated in linear zone.According to the empty short and empty disconnected characteristic of desirable error amplifier, can get:

i0≈i2，U2≈U3＝0

And: $i0=\frac{U0-U2}{\mathrm{<figure-callout\; id="4"\; label="R"\; filenames="HSA00000615556700012.png"\; state="\{\{state\}\}">R</figure-callout>}4}=\frac{U0}{\mathrm{<figure-callout\; id="4"\; label="R"\; filenames="HSA00000615556700012.png"\; state="\{\{state\}\}">R</figure-callout>}4}$

$i2=\frac{U2-U1}{\mathrm{<figure-callout\; id="5"\; label="R"\; filenames="HSA00000615556700012.png"\; state="\{\{state\}\}">R</figure-callout>}5}=-\frac{U1}{\mathrm{<figure-callout\; id="5"\; label="R"\; filenames="HSA00000615556700012.png"\; state="\{\{state\}\}">R</figure-callout>}5}$

Can draw thus: $U1=-\frac{U0}{R4}R5$

Following formula shows that U1 voltage and sampled voltage U0 are the scale operation relations, and the negative sign in the formula is represented U1 and U0 anti-phase, because U0 is the voltage of bearing, so U1 is exactly a positive voltage.If R4 is identical with the R5 value, then U0 equates with the amplitude of U1.

R3, R4, R5, R6, C2 have constituted proportional-integral controller jointly, pi regulator just, and it can guarantee the stability and the control precision of system.

3. N1B is another road error amplifier of LM124, also is operated in linear zone.U1 delivers to the inverting input of N1B, and degree of depth voltage negative feedback guarantees the error amplifier steady operation.R7, R8 provide reference voltage U5, after U5 and U1 relatively amplify, obtain error voltage U7.Go U7 controlling and driving control signal pulsewidth τ or cycle T realize (adjusting of D=τ/T), the final voltage stabilizing control that realizes the output negative high voltage to duty ratio D.Regulator potentiometer R8 changes reference voltage U5, can adjust the output voltage of negative high voltage power source.

R10, R11, R12, C3, C4 have constituted scale operation circuit, integral operation circuit and differential operation circuit, PID adjuster just, and it had both guaranteed the stability and the precision of system, had also improved the response speed of system.

Claims (3)

1. The application process of single supply error amplifier in the negative high voltage power source control circuit is characterized in that:

   1. adopt the single supply error amplifier, the passing ratio computing, differentiate, negative high voltage power source output voltage sampled signal is carried out anti-phase for integral operation etc. and error is amplified, and obtains error voltage signal.
2. 2. use PI and PID adjuster, both guaranteed the stability and the precision of system, also improved the response speed of system.
3. 3. the kind of negative high voltage power source mesolow power supply reduces, and Drive and Control Circuit is simple, reliable.

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