A Voltage Compensation Circuit for Adaptive Load Cable

Abstract

A voltage compensation circuit for an adaptive load cable. Firstly, the operation module is used to convert the output voltage of the error amplifier containing the peak current limit information of the primary feedback flyback converter into a first value related to the output current of the primary feedback flyback converter. intermediate voltage, and then perform level-shift conversion on the first intermediate voltage to obtain a second intermediate voltage that can adapt to the common-mode input range of the voltage-current conversion module, and then perform ripple elimination conversion on the second intermediate voltage to obtain a third intermediate voltage. The three intermediate voltages pass through the voltage-current conversion module to obtain the corresponding current and generate a voltage drop on the fifth resistor to obtain a compensation voltage proportional to the output current. The compensation voltage is superimposed on the reference voltage adjusted by the system loop to obtain the load cable The new compensated reference voltage is used for loop adjustment of the system, so that the output voltage of the primary side feedback flyback converter can adapt to change with the load current to ensure the stability of the actual charging voltage.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and relates to a voltage compensation circuit for an adaptive load cable, which can be applied to a primary-side feedback flyback converter controlled by constant voltage, so that the output voltage of the primary-side feedback flyback converter passes through the load The actual charging voltage provided to the load behind the cable is constant. Background technique [0002] The wide use and increasing development of portable electronic products have made the power supply industry market flourish and become larger and larger. At the same time, the market's requirements for power supply products are becoming more and more stringent. Lithium batteries can provide 3-4 times the power of lead-acid batteries of the same volume due to the amount of charge released per unit mass (ie specific capacity) as high as 3861mAh / g. In the application of portable electronic products, lithium ...

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Problems solved by technology

[0006] Aiming at the shortcomings in the above compensation scheme that directly affect the sampling and control of the loop and the inability to self-adaptively generate compensation voltage, the present invention proposes a voltage compensation circuit for adaptive load cables. The error amplifier output voltage VC of the excitation converter peak current limit information generates the compensation voltage V of the adaptive load cable CABLE , and will compensate the voltage V CABLE Superimposed on the reference voltage VREF adjusted by the internal loop of the primary-side feedback flyback converter, the compensated reference voltage VREFC makes the output node voltage of the primary-side feedback flyback converter increase with the increase of the load current, thereby offsetting The consumption voltage of the load cable realizes the compensation of the loss of the load cable under different load currents, and controls the actual charging voltage of the output node of the primary side feedback flyback converter to the load through the load cable to remain constant under different loads; and Because the solution of the present invention does not directly participate in and affect sampling, it will not affect the sampling and stability of the loop while improving the control accuracy of the system, and can be better applied to CC (constant current) / CV (constant voltage) control The primary side feedback flyback converter

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