SU758318A1 - Device for power supply of piezoceramic transducer of vibromotor - Google Patents

Description

The invention relates to the field of instrumentation and can be used to power the piezoelectric and magnetostrictive transducers of vibration motors. five

Known amplifiers with parallel excitation by a two-phase voltage, obtained from a transformer phase-inversion stage, in which two windings are connected to the base circuits of two, in series, transistors of the power amplifier, which are connected to the bases and collectors of the corresponding transistors £ ϊ ^ through resistors. 15

A disadvantage of the known devices is the low stability of the feedback voltage when the load changes.

A device for powering the 20 piezoceramic transducer of a vibromotor is known, which contains a resonant amplifier assembled on a transistor, in the collector circuit of which the U-loop is connected, winding the circuit 25 by means of a transformer coupling. interfaced with two windings, oppositely included in the base circuits of two series-connected transistors of the power amplifier, W-30

2

ry conclusions which through resistors are connected to the bases and collectors of the corresponding transistors £ 2].

A disadvantage of the known device is the low stability of the feedback voltage when the load changes. , \

The aim of the present invention is to increase the stability of the feedback voltage when the load changes and the increase of the speed, the excitation of oscillations at power up. '

In accordance with the invention, the goal is achieved by connecting a piezo-ceramic switch to the output of the power amplifier through a matching transformer, and in the secondary winding of the matching transformer, oppositely connected diodes are connected in series with the piezo-ceramic converter and connected to the base of the transistor of the resonant amplifier, as well as that between the point of connection of the diodes with the secondary winding of the matching transformer 'and the base of the transistor ansnogo amplifier included capacity.

-Ntigaaiag ·

, 758318

The figure shows the circuit diagram of the device. In the collector circuit of the transistor 1 of the resonant amplifier 2 is included a resonant circuit consisting of a capacitor 3 and a winding 4 of inductance associated with the windings 5,6 oppositely connected to the bases of the series-connected transistors 7.8 of the power amplifier 9. The second terminals of the windings 7.8 through resistors 10, 11 and 12, 13, respectively, are connected to the emitters and collectors of transistors 7.8. The output of the power amplifier 9 through the separation capacitor 14 is connected to the primary winding 15 of the matching transformer 16, in the secondary ob-. the coil 17 of which includes oppositely connected diodes 18 ,, piezoceramic converter 19 coupled to the rotor 20. The connection point of the diodes 18 to the secondary winding 17 of the matching transformer 16 is connected to the base of transistor 1 through a parallel connected resistor 21 and capacitor 22. The base of transistor 1 is connected through a resistor 23 to power supply.

The device works as follows. The signal from the winding 4 of the resonant amplifier 2 through a transformer coupling is supplied to two windings 5,6 connected opposite to the basic circuits of the transistors 7,8. This provides parallel two-phase excitation of the power amplifier 9. The signal from the output of the power amplifier through the coupling capacitor 14 and the matching transformer 16 is fed to serially connected pie-ceramic converter 19 and diodes 18. The frequency of the signal corresponds to the resonant frequency of pie-ceramic converter 19, performing mechanical oscillations with the highest amplitude and interacting with a rotor 20.

Part of the signal falls on the oppositely included diodes 18, which act as a positive feedback voltage limiter. The signal from the diodes 18 through the resistor 21 is supplied to the base of the transistor 1, in the collector circuit of which a HC-resonant circuit is connected, which selects the first harmonic of the limited signal. The frequency of the resonant circuit collected on the capacitor 3 and the winding 4 corresponds to the resonant frequency of the pieceramic converter 19. Thus, the device

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provides power to the piezoceramic transducer 19 with a frequency corresponding to its resonant frequency. When changing the mechanical load and temperature of the transducer 19, its resonant

5 frequency, and synchronously changing the frequency of the power signal. The inclusion of the capacitance C 22 contributes to an increase in the response rate

_ the signal power converter 19,

1® because when power is turned on, capacitor C 22 short-circuits the resistor 21. Resistors 23, 10, 11, 12, 13 determine the operating mode of the transistors 1.7.8.

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Claims (2)

Claim * 1. A device for powering a vibro-20 piezoelectric ceramic converter containing a resonant amplifier assembled on a transistor, in the collector circuit of which a HC circuit is connected, winding the circuit by means of transformer coupling mates with two windings oppositely connected to the base circuits of two series-connected transistors of the power amplifier, the second outputs of which through resistors are connected to the bases and collectors of the corresponding transistors, which is different in that with the aim of increasing stably ti feedback voltage when the load to the output of the power amplifier through conductive soglasuyu35 piezoceramic converter transformer is connected, wherein the secondary winding of the matching transformer in series with the converter pezokeoamicheskim 40 are connected oppositely connected diodes, which are connected via a resistor to the base of the transistor of the resonant amplifier. 2. The device according to claim 1, which is based on the fact that, in order to increase the excitation speed of the oscillations when the power is turned on, capacitance is switched on between the connection point of the diodes and the secondary winding of the matching transformer and the base of the rozo transistor.