A low-voltage cold-start circuit for energy harvesting suitable for indoor sunlight

Abstract

The invention discloses a low-voltage cold start circuit suitable for indoor sunlight energy collection, which relates to the field of sunlight energy collection and includes a ring vibration circuit, a two-phase clock drive circuit, a linear charge pump, an off-chip filter capacitor, and an off-chip storage circuit. Capacitor, enabling tube first PMOS tube, enabling tube second PMOS tube, third PMOS tube for dividing the output voltage of linear charge pump, fourth PMOS tube, fifth PMOS tube, sixth PMOS tube, voltage reference, current reference , hysteresis comparator, first inverter, and second inverter; the present invention can start at ultra-low voltage, satisfy a wide range of voltage input, and after cold start starts to work, the output of the internal linear charge pump is directly given to the chip The external energy storage capacitor is charged. When the off-chip energy storage capacitor stores enough energy, it outputs a higher voltage value, which can directly supply power to the subsequent circuit. When the output voltage of the cold start circuit exceeds the set value, the cold start circuit is turned off. The ring oscillator circuit and the two-phase clock drive circuit are used as overvoltage protection for cold start.

Description

technical field [0001] The invention relates to the technical field of energy harvesting cold start circuits, in particular to an energy harvesting low voltage cold start circuit suitable for indoor sunlight. Background technique [0002] The switched capacitor DC-DC boost circuit is a very critical circuit in the energy harvesting system. Usually in the energy harvesting application of photovoltaic cells or thermal energy battery energy sources, the circuit directly boosts the input voltage through the charge pump and outputs a higher voltage value. , using a linear charge pump can further reduce the cold crank output voltage value. Different from switching inductance DC-DC, in order to obtain higher voltage gain, Boost converter increases the duty cycle of the switching tube, even close to 1, which will increase the input current ripple, increase the conduction loss, and reduce the conversion efficiency of the entire circuit. The magnitude of the current output by the lo...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a low-voltage cold-start circuit suitable for indoor sunlight energy collection. The present invention solves the cold-start problem of low-voltage energy collection. Voltage boost to realize the boost function from the input source of the energy harvesting system to the output of the first stage

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