SU651310A1 - Voltage-comparing arrangement - Google Patents

Description

(54) DEVICE FOR COMPARING VOLTAGES

the transformer, and the control electrodes of the transistors connected to the sources of the compared voltages, are made on a matched pair of field-effect transistors, in the control circuit and one on which a mixing source is introduced, formed by the additional winding of the gating impulse transformer (stor, diode storage capacitor.

The drawing shows a diagram of the device.

The device contains a differential transformer 1 with symmetrical according to the included windings 2 and 3 in the output winding 4, Chemo-psi 2 and 3 together with a matched pair of field-effect transistors 5 and 6 form a power circuit, in the diagonal of which is included the output telescope 7 of the gate pulse transformer 8. The gates of transistors 5 and 6 are connected to the sources 9 and 1O of the comparable voltages 1V to each other, respectively, an additional winding 11 of the transformer 8, the diode 12 And the capacitor 13 form a bias source connected to right transceiver electrodes 5. The input terminal 14 of the device is connected to the primary winding 15 of the transformer 8.-. ::

The device works as follows.

At the time of entry of the gating pulse into the firing unit 15, the capacitor 13 is charged. , i; 4 - ;;, ....; ..,;:, ";; ,, ,,:,:

Under the action of the bias voltage / Uj .., on the capacitor 13, the operating point of the transistor 5 is shifted towards decreasing the current through the channel, and transistor 5 begins to play the role of a reference resistor in the left shoulder of the bridge circuit, we, ---- - -:: - - -

The channel resistance of the transistor 6 in the right shoulder of the bridge circuit is determined by the ratio of the voltages of the sources 9 and 10 UT .., H tT-iiv, Ti e.

for example a gate-isachek U

matched expression

and,

 BH2- VH1 CM

AT).

3rd

In case of equality of voltages 11, and transistors 5 and 6, they turn out to be - under the same potential, their channels are equal and the currents in windings 2 and 3 are also equal. Thanks to the willing inclusion of windings 2

and 3 magnetic fluxes in the core of the transformer 1 are mutually compensated and the signal at the output winding 4 is not available at the time of the next gating pulse.

If the compared voltages are equal, the resistance of the channel of the transistor 6 is greater or less than the resistance of the channel of the reference current of the anzistor 6, the gate of which is under constant

potential relative to the source. As a result, moments of gating pulses in winding 4 appear to be pulses of positive or negative polarity, the amplitude of which is proportional to the difference

From the expression (1) it follows that in order for the gate potential of the transistor 6 relative to the source to always be positive, ensuring a high input impedance of the bridge. schemes, you must choose the value

$ and

more than expected maximum

cm

input differences. On the other hand, the bias voltage should be less than the cut-off voltage TJ

transistor 5, i.e.

from

UnT ..

vx-mxhx

ots

cm

When the latter condition is fulfilled, the sensitivity of the comparison device is almost constant over a wide range of input voltages.

Claims (1)

1. USSR Author's Certificate No. 317.037. Q О5 В 1 / О1Д97О. 2, Author's Certificate of the USSR S No. 231222, Q O5 B 1 / O1, 1967. eight mr ./four Jl /five // L