Multiplier-divider and method thereof

Abstract

The invention discloses a multiplier-divider and a method thereof, which are used for multiplying input current by first input voltage and then dividing a product by second input voltage to generate output voltage so as to achieve the advantages of no need of a BJT (Bipolar Junction Transistor), high elasticity and simple circuit. The multiplier-divider comprises a sawtooth wave generator and a comparator, wherein the sawtooth wave generator is used for generating a sawtooth wave signal according to the second input voltage; the comparator is used for comparing the sawtooth wave signal with the first input voltage to generate a comparison signal; and the comparison signal is used for controlling that a capacitor is charged by the input current to generate capacitor voltage with promotional relation with the output voltage. The method comprises the following steps of: generating the sawtooth wave signal of which the period is inversely proportional to the second output voltage according to the second input voltage; comparing the sawtooth wave signal with the first input voltage to generate the comparison signal; charging the first capacitor by the input current according to the comparison signal to generate the capacitor voltage which has promotional relation with the output voltage; and controlling the first capacitor to discharge according to a clear signal.

Description

technical field [0001] The invention relates to a multiplication and division device and its method. Background technique [0002] Traditional multipliers and dividers are composed of bipolar junction transistors (Bipolar Junction Transistor; BJT), so there are many disadvantages caused by BJT. For example, BJT has a high temperature coefficient, so the output of its multiplier and divider is also affected by temperature; BJT has high gain, so the slight distortion of the input signal of its multiplier and divider may cause the output of multiplier and divider Influence, so the anti-noise ability of the multiplier and divider is poor; the linear operation range of BJT is narrow, thus limiting the range of the input signal of the multiplier and divider composed of it. [0003] U.S. Patent No. 6,812,769 proposes a multiplier and divider without using BJT. Although it eliminates the shortcomings caused by BJT, it requires a more complicated circuit, and the cycle of the sawtoo...

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Problems solved by technology

[0002] The traditional multiplier and divider is composed of bipolar junction transistors (Bipolar Junction Transistor; BJT), so there are many shortcomings caused by BJT

For example, BJT has a high temperature coefficient, so the output of its multiplier and divider is also affected by temperature; BJT has high gain, so the slight distortion of the input signal of its multiplier and divider may cause the output of multiplier and divider Influence, so the anti-noise ability of the multiplier and divider is poor; the linear operation range of BJT is narrow, thus limiting t

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