| 摘要 |
PURPOSE:To offset the error in accuracy between an A/D converter and a system by taking out the output which is proportional to the voltage of a power supply and the output of temperature from a multiplier. CONSTITUTION:In a multiplier 2, a divided voltage value VM of a power-supply voltage and a temperature output voltage VT are multiplied. The actual multipli cation in the multiplier 24 is operated by utilizing the logarithmic characteristic of a transistor constituting the multiplier 24. The relation between current values I1, I2 and I3 flowing through circuits for obtaining voltages VM, VT and VR and a current I4 flowing through a feedback resistor 27 of an operation amplifier 25 of an output part is imparted by the following expression: I4 = I1 X I2/I3. The product of the output current I4 and the resistance 27 is made to be an output voltage VOUT. Therefore, the relation between the voltages VM, VT and VR and the VOUT becomes as follows: VOUT = K X VM X VT/VR, where K is a constant which is determined based on the values of resistors 21, 22, 23 and 27. It is found that the voltage which is proportional to the power- supply voltage Vcc and the temperature is outputted based on the result. |
