SU1091336A1 - Voltage-to-time interval converter - Google Patents

Description

The invention relates to electrical parameters and can be used as a functional unit in special and universal measuring instruments and systems. Voltage transducers and time intervals are known, which include a switch, an operational amplifier and resistors, in which errors due to residual key parameters are completely eliminated. into chains of transformed and reference stresses ij. However, in these devices, the accuracy of the transducer 1 and ciTiecTBeHUbw depends on the stability of the ratio of the four resistors included in the conversion formula. In addition, these devices are distinguished by the complexity of the circuit implementation, which leads to increased power consumption by the circuit. The closest in technical essence to the present invention is a voltage converter in a time interval containing a key and a switch, two operational amplifiers, an input input of the first of which is connected to the first output of the first resistor, the first output of the key and the first plate of the integrating capacitor, the output of the first operational amplifier is connected to the first input of the switch, the output of which is connected to the second plate of the integrating capacitor, the output of the second op amp is connected to the second input of the switch, the control inputs of the key and the switch are connected to the corresponding outputs of the control unit, the first input of which is connected to the output of the voltage pulse generator of the reference voltage 2J, Disadvantages of the known the device is of low accuracy due to the instability of the resistances of the resistors in the circuits of the transformed and reference voltages and low input resistance s, target invention - povshyunie to.ch carry and converting the input resistance. The goal is achieved by the fact that in a voltage converter in a time interval containing a key and a switch, an operating amplifier, the inverting input of the first of which is connected to the first output of the first resistor, the first output of the key and the first plate of the integrating capacitor, the output of the first operational amplifier is connected with the first input of the switch, the output of which is connected to the second plate of the integrated capacitor, the output of the second operational amplifier is connected to the second input of the switch, pn The key and switch inputs are connected to the corresponding outputs of the control unit, the first input of which is connected to the output of the clock voltage generator of the reference voltage, an additional operational amplifier and key are inserted between the output and the inverting input of the additional operational amplifier, the specified input of which is connected to the second lining the integrating capacitor, a non-inverted input with a voltage reference and a non-inverting input of the second operational amplifier, inverting whose input is connected to the first output of the first resistor, the second output of which is connected To; the common bus, the non-inverting input of the first operational amplifier is connected to the converted signal bus, the output of the second operational amplifier is connected to the output of the key, and the output of the additional operational amplifier is connected to the second input of the control unit, and the control input of the additional key is connected to the control input of the ktpocha. Figs 1 and 2 respectively represent a functional diagram of a voltage-to-time converter and timing diagrams explaining its operation. The proposed device contains a resistor 1, a reference voltage bus 2, an operational amplifier 3, 4 and 5, keys 6 and 7, a switch 8, a capacitor 9j generator of 10 cycles, a control unit 11, points 12-15, the inverting input of the first operational amplifier 5 is connected with the inverting input of the second operational amplifier 3, the first plate of the capacitor 9 and through a resistor 1 is connected to the ground bus, the outputs of the first 5 and second 3 operational amplifiers are connected to the outputs of the switch 8, the input of which is connected to the second plate of the cortex 9 and the investor tiruyuschemu input of the third operational amplifier 4. The first switch 6 connects the output of the first operational amplifier 5 with its non-inverting input. The second switch 7 connects the output of the third operational amplifier 4 to its non-inverting input. The control inputs of the keys fi and 7 and the switch 8 are connected to the outputs of the control unit 11, and the inputs of the block 1 are connected respectively to the generator output of 10 cycles and the output of the operational amplifier 4. The bus 2 of the reference voltage is connected to the non-inverting inputs of the first 5 and third 4 operational amplifiers, the output of the circuit is the non-inverting input of the second operational amplifier 3, Diagrams 12-15 (big, 2) correspond to points 12-15 in FIG. 1, the voltage converter operates in the following time interval, at the beginning of the cycle At the time tg (FIG. 2) generated by the output from the generator of 10 cycles, the switch 8 connects the capacitor 9 plate to the output of the operational amplifier 3. As a result, the capacitor 9 is charged with a current proportional to the input voltage U and at time t , 2) the capacitor 9 is charged to the voltage Ux (t, -to) where R and C- are the values, respectively, of the resistor 1 and the capacitance of the capacitor 9, At time t, the switch 8 connects the capacitor 9 capacitor output to the output of the operational amplifier 5 causing conden The capacitor is discharged by a current proportional to UQ. The time t (FIG. 2), whose value is determined from the relation U, (t, -tp) Uo (tg-t.) R | Co is characterized by the equal to zero voltage on the capacitor 9, At this point in time the output voltage of the operating voltage the amplifier 4 changes abruptly and sets the trigger of the block 11 to the single state. As a result, the keys 6 and 7 are opened, the voltage on the capacitor 9 is fixed to zero, the keys fi and 7 remain open until the beginning of the next conversion cycle (the moment t , fig, 2), when the command from the generator 10 cycles. the trigger of block 11 is reset. The informative time interval DT (t, -tj does not depend on the values of the parameters of the circuit elements. Compared to the prototype device, the conversion accuracy is improved by facilitating the operation of the reference voltage source, which in the proposed device operates practically in idle mode at constant load Because of this, a normal element can be used as a source of reference voltage in the device, since there is no strict requirements, the source of Ug can be low-power, Thus, at the same time as the accuracy is increased, a reduction in power consumption is achieved.For the comparison of technical and economic indicators, a microelectronic voltage converter in the US National Semikand time interval of 5863 has been selected as the basic object. , 05%, the power consumption of the NVD is 570 mW, the conversion time is 40 ms. Unlike the base object, the proposed converter uses a normal element as a reference source, which makes it possible to reduce power consumption by 2 times. At the same time, the accuracy, which in the base object is determined by the stability of the reference source, can be increased by an order of magnitude in the device, since, unlike stabilizers used as a reference source, the stability of a normal element is an order of magnitude higher. Thus, we can conclude that the technical and economic indicators of the proposed device, taking into account the reasonable prospects of its manufacture and microelectronic performance, are quite high.

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Claims (1)

THE INTERVAL VOLTAGE CONVERTER, containing a key and a switch, two operational amplifiers, an inverting input of the first of which is connected to the first output of the first resistor, a key input and the first lining of the integrating capacitor, the output of the first operational amplifier is connected to the first input of the switch, the output of which is connected to the second integrating capacitor plate, the output of the second operational amplifier is connected to the second input of the switch, the control inputs of the key and switch are connected to the corresponding outputs of the control unit, the first input of which is connected to the output of the reference voltage clock generator, characterized in that, in order to increase the conversion accuracy and input resistance, an additional operational amplifier and a key are inserted into it, connected between the output and the inverting input of the additional operational amplifier, the specified input of which is connected to the second lining of the integrating capacitor, a non-inverting input with a voltage reference bus and a non-inverting input of the second an operational amplifier, the inverting input of which is connected to the first output of the first resistor, the second output of which is connected to a common bus, while the non-inverting input of the first operational amplifier is connected to the bus of the converted signal, the output of the second operational amplifier is connected to the output of the key, and the output of the additional operational amplifier is connected to the second input of the control unit-> singing, and the control input of the additional key is connected to the control input of the key. SU „„ 1091336