A start-up circuit of a bandgap reference voltage source

Abstract

The invention provides a starting circuit of a band-gap reference voltage source. The starting circuit is characterized by comprising a first phase inverter, a second phase inverter, a first transistor, a second transistor and a third transistor, wherein the positive end of a power supply of the first phase inverter is connected with the output voltage of the band-gap reference voltage source, theinput end of the first phase inverter is grounded, the output end of the first phase inverter is connected with the control end of the first transistor, the input end of the first transistor is connected with the output end of the second transistor and the input end of the second phase inverter, and the output end of the first transistor is grounded; the input end of the second transistor, the input end of the third transistor and the positive end of a power supply of the second phase inverter are connected with supply voltage (VDD); the control end of the second transistor is further connected with the output end, and the control end of the third transistor is connected with the output end of the second phase inverter; the drain electrode of the third transistor serves as a starting voltage output end. The starting circuit adopts a full-digital mode without any static power consumption, the starting circuit is not affected by the supply voltage, the structure is simple, and a required chip area is small.

Description

technical field [0001] The invention relates to the field of power circuits, in particular to a starting circuit of a bandgap reference voltage source. Background technique [0002] The domestic mobile phone market is booming. According to a survey by the High-tech Lithium Battery Industry Research Institute, China’s mobile phone shipments reached 1.25 billion units in 2012, and the mobile phone lithium battery market reached 23.2 billion yuan (including PACK). Lithium-ion batteries are basically used in mobile phones. According to the requirements of different electronic products, they can be made into flat rectangle, cylinder, rectangle and button type, etc., and several batteries can be connected in series and parallel to form a battery pack. The rated voltage of lithium-ion batteries is generally 3.7V due to changes in materials, while that of lithium iron phosphate (hereinafter referred to as iron phosphorus) positive electrode is 3.2V. The termination charging voltage...

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Problems solved by technology

[0004] The traditional bandgap reference voltage source adopts the technique of canceling the positive temperature coefficient and the negative temperature coefficient, which can generate an output voltage that is constant with the power supply voltage and temperature. It has been widely used in various analog and mixed signal products. This circuit has full The advantages of integration, low power consumption, and simple and convenient implementation; but because the circuit has two working states of normal working current and zero current, a startup circuit is needed to ensure the normal operation of the circuit

But the traditional start-up circuit often requires quiescent working current, so it is not suitable for ultra-low power consumption applications; and in order to achieve a very low current to ensure the start-up circuit works, it often needs a large resistor and transistor to achieve, which will occupy large chip area

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