BRIDGE CIRCUIT IMBALANCE VOLTAGE CONVERTER TO FREQUENCY OR DUTY RATIO Russian patent published in 2019 - IPC G01R17/10 H03M1/12 

FIELD: measuring equipment.

SUBSTANCE: bridge circuit imbalance voltage converter to frequency or duty ratio relates to information and measurement equipment and can be used in precision converters of physical parameters (linear acceleration, pressure), magnetometers, devices for measuring galvanically isolated currents, in electrothermal converters (flow meters) in frequency or duty ratio. Bridge circuit imbalance voltage converter to frequency or duty ratio comprises a first operational amplifier, a non-inverting amplifier, a first resistive divider, a first resistor, a capacitor, an analog switch with a control input, an output device, a bridge circuit, the first input of which is connected to the power supply, the integrator formed by the first operational amplifier, the first resistor and the capacitor, first lead of first resistor is connected to inverting input of first operational amplifier and through capacitor is connected to its output, second resistive divider, non-inverting voltage comparator, second resistor, symmetrical differential voltage amplifier with zero offset input, third resistor integrating RC circuit. Non-inverting amplifier may comprise third and fourth resistors, a second operational amplifier, non-inverting input of which will be second input of non-inverting amplifier, and the inverting input is the first input of the non-inverting amplifier, which through the third resistor is connected to the common bus and through the fourth resistor to the output of the second operational amplifier, the output of which will be the output of the non-inverting amplifier. Output device can be made in the form of a pulse amplitude generator, which facilitates subsequent decoding of frequency signals and, in particular, duty ratio without distortion associated with regulation of voltage at the input power input of the input non-inverting voltage comparator. Bridge circuit can be made on passive elements if resistance of bridge circuit arms is small, or on active elements (for example, in the form of voltage repeaters) for matching with a differential amplifier.

EFFECT: broader functional capabilities, high stability of frequency or duty ratio when varying supply voltage, with synchronous temperature change of initial resistance of arms of bridge circuit, high stability of frequency or duty ratio due to high speed and detection of change of parameters of time-setting RC-circuit (calibration) by determining initial frequency at short-circuiting outputs of bridge circuit or their disconnection and simplification of implementation due to use of unipolar power supply.

7 cl, 3 dwg