Channel of Measurement and Indication of 220 Voltage in the Device «Quality-E1»

At the V.M. Glushkov Institute of Cybernetics the “Yakist-E1” – electric power quality measuring device, was developed. The device uses new method and structure of a quality determination, and is based on calculating the deviations from the nominal values of voltage and frequency values. The methodical error of level quantization for a 10-bit ADC is ± 0.1%. To achieve an approximation error of ± 0.1%, it is necessary to measure the voltage near the amplitude value after 170 μs. The channel for voltage measuring in the device consists of a voltage transformer, a high-precision resistive divider that scales and biases the input voltage, a reference voltage source (VREF) and an ADC, which built into the microcontroller. The device “Yakist-E1” uses an 8-bit microcontroller type C8051F320, which has a 10-bit ADC with an input signal range from 0 to 2.5 V. The output voltage of the VREF from the chip to the controller chip can vary from 2.38 V to 2.5 V. In addition, different transformer sensors may have different transfer characteristics, which may be non-linear. Therefore, to indicate the values of the measured voltage on the alphanumeric indicator, a piecewise linear approximation of the results of measuring the ADC is used. The transfer and temperature characteristics of the voltage transformer were measured for forward and reverse passages, and, according to the results, was discovered that the temperature error is very small and practically does not affect the accuracy of the sensor and the sensor has hysteresis, the calculated errors do not exceed ± 1%. All this errors were corrected. To determine the deviation of the amplitude value from the nominal value, only 8 low-order bits of the ADC are used. This trick grants that ADC result can be processed by a single command of the microcontroller, which increases processing speed of the channel.

A novel high accuracy bandgap reference voltage source

Purpose This paper aims to design a new bandgap reference circuit with complementary metal–oxide–semiconductor (CMOS) technology. Design/methodology/approach Different from the conventional bandgap reference circuit with operational amplifiers, this design directly connects the two bases of the transistors with both the ends of the resistor. The transistor acts as an amplifier to amplify the change of voltage, which is convenient for the feedback regulation of low dropout regulator (LDO) regulator circuit, at last to realize the temperature control. In addition, introducing the depletion-type metal–oxide–semiconductor transistor and the transistor operating in the saturation region through the connection of the novel circuit structure makes a further improvement on the performance of the whole circuit. Findings This design is base on the 0.18?m process of BCD, and the new bandgap reference circuit is verified. The results show that the circuit design not only is simple and novel but also can effectively improve the performance of the circuit. Bandgap voltage reference is an important module in integrated circuits and electronic systems. To improve the stability and performance of the whole circuit, simple structure of the bandgap reference voltage source is essential for a chip. Originality/value This paper adopts a new circuit structure, which directly connects the two base voltages of the transistors with the resistor. And the transistor acts as an amplifier to amplify the change of voltage, which is convenient for the feedback regulation of LDO regulator circuit, at last to realize the temperature control.