Double-supercapacitor light emitting pen circuit

Abstract

The invention provides an electronic whiteboard light emitting pen circuit without battery charging. A scheme of double supercapacitors is adopted. On the premise of hardly changing overall capacity of the capacitors, the discharging time is greatly delayed, and the utilization rate of the capacitors is improved. The circuit comprises a charging circuit, a control circuit, a light emitting driving circuit and a main supercapacitor, wherein the circuit is additionally provided with an auxiliary supercapacitor, the charging circuit is also connected with the auxiliary supercapacitor to charge the auxiliary supercapacitor, the main supercapacitor is used for independently supplying power to the light emitting driving circuit, the auxiliary supercapacitor is used for independently supplying power to the control circuit, and the capacity of the main supercapacitor is much more than the capacity of the auxiliary supercapacitor. The circuit has the beneficial effect that after the very small auxiliary supercapacitor is additionally arranged, the working time of the light emitting pen after being charged at each time can be extended by about 70%.

Description

technical field [0001] The invention relates to a circuit of an electronic pen, in particular to a circuit of a double supercapacitor light-emitting pen used for a light-emitting pen of an electronic whiteboard. technical background [0002] In the electronic whiteboard system based on image processing, a luminescent pen is used. Such luminescent pens generally emit infrared light to indicate the location. In such a pen there must be a power supply. Existing products generally use disposable batteries or rechargeable batteries as power sources, which have the following disadvantages: 1. Ordinary batteries or rechargeable batteries have serious environmental pollution during the production process and after they are discarded; 2. Ordinary batteries are expensive to use as consumables. In order to facilitate battery replacement, the structure of the pen is more complicated; 3. The battery has potential safety hazards in transportation and storage; 4. The service life of the ...

AI Technical Summary

Problems solved by technology

Existing products generally use disposable batteries or rechargeable batteries as power sources, which have the following disadvantages: 1. Ordinary batteries or rechargeable batteries have serious environmental pollution during the production process and after they are discarded; 2. Ordinary batteries are expensive to use as consumables. In order to facilitate battery replacement, the structure of the pen is more complicated; 3. The battery has potential safety hazards in transportation and storage; 4. The service life of the rechargeable battery is short, and the capacity drops rapidly in the later period of use

In this way, if two supercapacitors are used in series to charge, the partial voltage of each capacitor is 2.5V, and its capacity cannot be fully utilized, and the voltage imbalance between the two capacitors in series is very likely to cause overvoltage damage; and if parallel or single Supercapacitor charging as the only power supply also has problems, that is, although the forward voltage of the light-emitting tube is low, the control circuit in the light pen generally requires a working voltage of more than 2V, so the discharge range of the supercapacitor is only 2.7V- 2V=0.7V, the capacity of the supercapacitor cannot be fully utilized, and the discharge time is too short

At present, in the existing product design, the method of increasing the capacity of the supercapacitor is used to prolong the discharge time, but this increases the volume of the product, and the cost also increases accordingly, which is a great disadvantage for the luminescent pen product.

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