JP3393900B2 - Class E amplifier with shunt LC resonant circuit inserted - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the fields of communication, information equipment, and electronic equipment which require a small and highly efficient power converter. For example, it can be used as a power supply circuit used for portable communication devices and information devices, a power supply circuit used for artificial satellites, and a small and high-efficiency power supply circuit for RF output such as a medical RF radio wave generator and a microwave oven.

[0002]

2. Description of the Related Art A class E amplifier which is the basis of the present invention is a DC-R.
The F power converter is composed of a single-ended switching element and a passive load, and operates using the combined effect of switching and load transient response. RF sine wave current is supplied to the output, and the switch voltage and its derivative become zero at the moment when the switch turns from off to on to prevent the loss due to the switching of the power stored in the capacitor in parallel with the switch. , Then the current is designed to rise from zero.

Therefore, in high frequency operation, power loss due to switching can be extremely reduced. The output power of the class E amplifier is uniquely determined by the conditions for causing the class E operation when the input voltage, the output resistance, and the output Q value are determined. Further, the output is adjusted by a frequency control that keeps the OFF time of the switch constant and changes the ON time, or a simple frequency control that maintains only a zero voltage condition called quasi-E class.

[0004]

In the conventional class E amplifier, the input voltage, the output Q value, the operating frequency (the switch O
If the output power or the load resistance (10) is determined when the N and OFF frequencies are constant, the other is determined, and the degree of freedom in design is limited. Further, the output control is performed by a complicated frequency control method in which the OFF time of the switch is fixed and the ON time is changed, or a frequency control method of only the zero voltage condition.

With respect to the above problems, the output power and the resistance value can be independently set, the output control can be easily adjusted, and the switch voltage at turn-on and its differential coefficient are both maintained at zero. It is an object of the invention to enable.

[0006]

A capacitor (5) in parallel with a switch (3) and a capacitor (5) of a class E amplifier.
An LC series resonance circuit composed of an inductor (6) and a capacitor (7) is inserted in parallel with and the part is added to the design.

Both or one of the inductor (6) and the capacitor (7) is controlled so as to maintain the class E operating condition in response to a change in load resistance and a change in required output power.

[0008]

In the conventional class E amplifier, the DC current (12) is supplied from the DC power supply (1) through the choke coil (2).
A switch (3) and a capacitor (5) in parallel with it.
And (8), (9) and (10). The output is a sine wave, and the difference between the input current (13) and the output current (16) is the switch (3) and the capacitor (5).
Flow alternately. Therefore, if the input and the load are determined, the output is determined, but in the circuit of claim 1, an LC series circuit composed of an inductor (6) and a capacitor (7) in parallel with the switch (3) and the capacitor (5). A resonance circuit is inserted and a current (15) is passed through it.

This current (15) can be freely set in both amplitude and phase by the values of the inductor (6) and the capacitor (7). Therefore, the relationship between the input and the output at the time of design can be selected while maintaining the class E operating condition.

Further, in the operation of the prepared circuit, the switching voltage (17) is changed by changing the amplitude and the phase with respect to the change of the load resistance and the change of the required power by the control method according to the second and third aspects.
Can be adjusted while satisfying Class E operating conditions.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a class E amplifier in which the shunt L-C resonant circuit according to claim 1 is inserted. The circuit configuration is basically the same as that of the conventional class E amplifier except that there is a shunt LC resonant circuit (a series resonant circuit composed of (6) and (7)).

The switch (3) is an N-type MOSFET and has a diode (4) in antiparallel from the source to the drain. The switch is ON at the operating frequency f,
Turn off. The output current (16) and the current flowing through the shunt L-C resonant circuits (6) and (7) are sine waves with the operating frequency f.

Series resonant circuits (8) (9) and (6)
(7) is a pure filter for the operating frequency,
It consists of reactance components. The reactance component of the shunt L-C portion changes the amplitude and phase of the output current (16) by changing (6) or (7) or both. This change changes the amplitude and phase of the output current (16).

Although this circuit is designed to include the shunt L-C portion, the switch voltage (1
It is possible to control the output while keeping the waveform of 7) in class E. Therefore, high efficiency can be maintained.

[0015]

Since the present invention is constructed as described above, it has the following effects.

That is, the shunt LC resonance circuit (6)
By inserting (7), setting of output power and input condition can be selected. Further, by adjusting this portion, it is possible to control the output while keeping the waveform in class E.

Further, since the switch switches while satisfying the class E operating condition in a strict sense, high efficiency can be maintained. This circuit can maintain a strict class E operating condition by simple element value control instead of switching frequency control, which is a problem in terms of measures against noise and enlargement of resonant element.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a class E amplifier in which a shunt LC resonance circuit is inserted.

[Explanation of symbols]

1 DC power supply 2 choke coil 3 switches 4 diode 5 shunt capacitors 6,8 inductor 7,9 Capacitor 10 load resistance 11 earth 12 Input current 13 Switch current 14 Capacitor current 15 shunt L-C current 16 Output current 17 Switch voltage 18 Output voltage

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Claims (3)

(57) [Claims] 1. At least a single-ended connection switch.
A switching element and a passive load.
Switching of switching elements and transient response of the passive load
DC power is converted into AC power by class E operation based on the combined effect of
In a class E amplifier for converting into force, an inductor and a capacitor are provided in parallel with the switching element.
Characterized by connecting an LC series resonant circuit consisting of a shaft
Class E amplifier. 2. A switch having at least a single-ended connection.
A switching element and a passive load.
Switching of switching elements and transient response of the passive load
DC power is converted into AC power by class E operation based on the combined effect of
In a method of controlling a class E amplifier for converting into force, an inductor and a capacitor are provided in parallel with the switching element.
Connect the LC series resonant circuit consisting of
The value of at least one of the
Class E amplification for changing the output power of the Class E amplifier by
Control method. 3. At least a single-ended connection switch.
A switching element and a passive load.
Switching of switching elements and transient response of the passive load
DC power is converted into AC power by class E operation based on the combined effect of
In a method of controlling a class E amplifier for converting into force, an inductor and a capacitor are provided in parallel with the switching element.
Connect the LC series resonant circuit consisting of
The value of at least one of the
To maintain the class E operating conditions of the class E amplifier by
Amplifier control method.