JPH1022759A - Control circuit for high frequency power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate overshooting effect accompanying intermittent output and to accelerate an operation by holding the value of detected high frequency power and sending it to an error amplifier. SOLUTION: The output of a high frequency oscillator 0 is passed through a current controlled high frequency attenuator 1 and a high frequency power amplifier 2 and turned to the output of a high frequency power generator 11. A pulse voltage generator 7 intermittently changes the attenuation amount of the current controlled high frequency attenuator 1 by intermittent pulses and turns the output of the high frequency power generator 11 to the intermittent output. In this case, a sample-and-hold amplifier 10 holds the high frequency power of a period when the high frequency power is outputted, based on the signals of the pulse voltage generator 7 through a high frequency power detector 3 and sends it to the error amplifier 4. The error amplifier 4 generates control signals with a reference voltage 6 as a reference and sends them through a voltage controlled switch 5 to the current controlled high frequency attenuator 1, based on the signals of the pulse voltage generator 7. Regardless of the intermission of the high frequency power, the error amplifier 4 is operated by continuous signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for a high-frequency output of a high-frequency power generator.

[0002]

2. Description of the Related Art FIG. 1 shows a system diagram of a conventional high frequency generator. In FIG. 1, 0 is a high frequency oscillator, 1 is a current control type high frequency attenuator, 2 is a high frequency power amplifier, 3 is a high frequency power detector, 4 is an error amplifier, 5 is a voltage control type switch, and 6 is an output power setting reference. The voltage 7 is a pulse voltage generator. In addition, 12 is a resistor, and 13 is a capacitor.

The high frequency power generated by the high frequency oscillator 0 is
It is intermittently attenuated by the current control type high frequency attenuator 1, power-amplified by the high frequency power amplifier 2, passes through the high frequency power detector 3, and obtains an intermittent output of high frequency power.

The voltage detected by the high frequency power amplifier 3 is
The voltage of the output power setting reference voltage 6 is compared and amplified by the error amplifier 4 with the pulse-shaped reference voltage switched by the voltage control switch 5 and applied to the current control high frequency attenuator 1.

In this method, the detection voltage of the high-frequency power detector 3 and the reference voltage 6 for setting the output power are operated so that the pulse-like voltage switched by the voltage control switch 5 becomes the same. Due to a delay in detection by the power detector 3, a capacitor 13 for phase correction must be added to the error amplifier 4 to suppress overshoot or oscillation. For this reason, the rise and fall times of the intermittent output cannot be shortened to a certain extent.

[0006]

SUMMARY OF THE INVENTION As described above, according to the present invention, even if a phase correction capacitor for suppressing oscillation is added to the error amplifier, there is almost no overshoot and the influence of the capacitor is eliminated. Provided is a control circuit for a high-frequency power generation device capable of obtaining an intermittent output with no rise, fast rise and fall time.

[0007]

2 shows an embodiment of the present invention, wherein 0 is a high-frequency oscillator, 1 is a current-controlled high-frequency attenuator, 2 is a high-frequency power amplifier, 3 is a high-frequency power detector, 4 is an error amplifier, and 5 is an error amplifier. Voltage control type switch, 6 is reference voltage for output power setting, 7
Is a pulse voltage generator, 10 is a sample hold amplifier,
11 is a high-frequency power generator, 12 is a resistor, and 13 is a capacitor.

The operation of the sample-hold amplifier 10 and the voltage-controlled switch 5 is such that, when the voltage-controlled switch 5 is turned on in synchronization with the pulse of the pulse voltage generator 7, the sample-hold amplifier 10 is in the sample state. When the voltage control switch 5 is off, the sample hold amplifier 10 is in a hold state.

(3) When the output current of the error amplifier 4 becomes an intermittent current by the voltage control type switch 5, the amount of attenuation of the current control type high frequency attenuator 1 changes intermittently, and the high frequency power generator 11
, An intermittent high-frequency output is obtained. Although the detection voltage of the high-frequency power detector 3 is an intermittent voltage at point A, the output of the sample-hold amplifier 10 continuously outputs the voltage at the time of the intermittent output. The voltage at the point B is compared with the reference voltage of the output power setting reference voltage 6,
A current is output from the error amplifier 4 so that these become the same.

In this system, even if the high-frequency output is an intermittent output, the error amplifier 4 operates as if it controls a continuous output. Due to such an operation, the high-frequency output has no overshoot at the time of the intermittent output, and the rise and fall times at the time of the intermittent output are fast without being affected by the phase correcting capacitor 13. It's time.

[0011]

According to the present invention, the overshoot during the intermittent output of the high-frequency output is eliminated, and the intermittent output is not affected by the phase correcting capacitor of the control error amplifier. Can be obtained. For this reason,
Pulse modulation at a high pulse frequency of the high frequency generator becomes possible.

[Brief description of the drawings]

FIG. 1 is a control circuit for obtaining an intermittent output of a conventional high-frequency power generator.

FIG. 2 is an embodiment of a control circuit for obtaining an intermittent output of the high-frequency power generator of the present invention.

[Explanation of symbols]

 0 High-frequency oscillator 1 Current-controlled high-frequency attenuator (DBM) (4) 2 High-frequency power amplifier 3 High-frequency power detector 4 Error amplifier 5 Voltage-controlled switch 6 Reference voltage (for setting output power) 7 Pulse voltage generator 10 Sampler Negative amplifier 11 High frequency power generator 12 Resistance 13 Capacitor

Claims (1)

[Claims] In a case where an intermittent output is performed by a high-frequency power generation device, a period in which an intermittent output is detected is sampled by a sample hold amplifier for a detection output voltage of the traveling wave power of the output, and a period in which there is no intermittent output. Hold state,
The output voltage of the sample hold amplifier is compared with a reference voltage by an error amplifier, and a switch is provided at the output of the error amplifier. Wherein the output is connected to a current-controlled high-frequency attenuator to control high-frequency power.