Resistors in Parallel. The essential concepts of resistors in parallel are explained both conceptually and mathematically. From the Physics course by Derek Owens.
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Waste batteries may be small, against Queshen big. However, due to pollution, waste batteries do not like waste, air and water pollution, as could any sensory feel it has great hidden, so did not receive due attention. At present, China’s Dell gd761 battery production and consumption to become a big country, and used batteries pollution is an urgent need to address a major environmental problem. According to environmental experts, in the recovery of waste batteries per 1,000 grams of metal, of which there are 82 grams of mercury, 88 grams cadmium, can be said that disposal of waste batteries recycling is not only addressed the sources of pollution, but also achieve the recycling of resources. In developed countries the recycling of spent batteries and use very seriously. Many countries in Western Europe, not only in stores, but also directly on the street are equipped with a special battery recycling box, and used batteries are 95% of the material can be recycled, particularly in high-value metal recovery. Such as the Foreign Secondary Lead industry developed rapidly, the current lead 55% of all production comes from regenerated lead. The Secondary Lead Industry in dealing with the regeneration of waste lead-acid batteries account for a substantial portion. 100 kg of waste lead-acid batteries can be recycled 50 to 60 kilograms of lead. Cadmium batteries for the regeneration of waste treatment technology abroad, have been more mature to deal with 100 kilograms of cadmium battery scrap recycling about 20 kg of metal cadmium, mercury batteries are mainly used for the environmentally sound processing means to prevent the pollution of the environment . However, there are in this area of management rather weak.
Note: Do not connect both ends of the battery, otherwise the battery will short-circuit, damaging the battery Lithium-ion Dell gd761 battery Protection Circuit Design A circuit design
1.1 Circuit Overview
Lithium-ion battery protection circuit includes over-charge protection, over current / short circuit protection and over-discharge protection, the circuit is to ensure that such over-charge and discharge status of the safety and to prevent the characteristic deterioration. It is mainly protected by the integrated circuit IC, chip resistors, chip capacitors, field effect transistor (MOSFET), and some even thermistor (NTC), identify the resistance (ID), fuse (FUSE) and other accessories. The circuit shown in Figure 1.
Lithium-ion Battery Protection Circuit
One integrated protection circuit protection circuit IC is used to detect the current voltage, current, time and other parameters in order to control the FET switch state; field effect transistor (MOSFET) is under the protection of IC to control the loop whether it might be open or closed ; chip resistors used for current-limiting; Chip Capacitors role is to filter, adjust delay time; thermistor is used to detect the ambient temperature inside the cell block; fuse to prevent the current flowing through the battery is too large, cut off the current loop.
1.2 Circuit principle and parameter determination
1.2.1 The over-charging protection
When the charger for lithium battery overcharge, the lithium batteries will be a result of temperature rise caused by increased internal pressure required to terminate the current charge state. At this point, integrated protection circuitry required to detect the battery voltage IC, when the arrival time 4.25V (assuming the battery charging voltage over the critical point at 4.25 V) that is activated over-charge protection, will-power MOS from the opening to cut off, then cut-off charge. In addition, in order to prevent excessive because the noise generated by the miscarriage of justice charge for overcharge protection, so need to set the delay time and delay time can not be shorter than the duration of the noise so as to avoid miscarriage of justice. Overcharge protection delay time tvdet1 calculated as follows:
t vdet1 = (C3 × (Vdd – 0. 7)) / (0. 48 × 10 – 6) (1)
Where: Vdd for the protection of N1 Over-charge detection voltage value.
Simple calculation of delay time: t = C3 / 0. 01 × 77 (ms) (2)
Should the value of C3 capacity 0.22 F, then the delay value is: 0. 22 / 0. 01 × 77 = 1694 (ms)
1.2.2 over-discharge protection
In the case of excessive discharge, the electrolyte decomposition due to deterioration caused by the battery characteristics and result in reduced number of charge cycles. Over-discharge protection IC principle: In order to prevent excessive battery discharge status, assuming that lithium battery connected to the load, when the lithium battery voltage is lower than the over-discharge voltage detection point (assumed to be 2.3 V) will activate the over-discharge protection, so that power MOS FET transition from open-cut and the cut-off discharge, in order to avoid battery over-discharge phenomenon, and will keep the battery at low quiescent current standby mode, at this time current is 0.1?A. When the lithium battery connected to the charger, and lithium Dell gd761 battery voltage is higher than at this time of excessive discharge voltage, over-discharge protection be lifted. In addition, taking into account the charge and discharge pulse the case, over-discharge detection circuit with delay time in order to avoid malfunction.
1.2.3 Over-current and short-circuit current protection
Because of unknown reasons (discharge or are negative by metal objects inadvertently) caused by over-current or short circuit, in order to ensure safety, you must immediately cease its discharge. Principles of over current protection IC, when the discharge current is too large or short circuit conditions arise, the protection IC will be activated off (short circuit) current protection, over current detection at this time is to power MOSFET’s Rds (on) as a sensor for monitoring the impedance the voltage drop in the case, if the ratio set by the overcurrent detection voltage is higher then the stop discharge, computing formula is:
V_ = I × Rds (on) × 2 (V_ for the over-current detection voltage, I is discharge current) (3) assumes V_ = 0. 2V, Rds (on) = 25 m?, while protecting current size of I = 4 A.
Similarly, over-current detection delay time must also be provided to prevent current flow generated when there are unexpected malfunction. Usually after the election of over-current if they can remove the over-current factors (such as immediately and load out) will resume its normal state, can then carry out the normal charge-discharge action. 2 Conclusion
Carrying out protection circuit design to a full Dell 312-038 battery charge state is the user’s concern, taking into account the security problems and therefore need to allow the voltage to reach cut-off state of charge. To simultaneously satisfy these two conditions, there must be a high precision detector, current detector precision of 25 mV. Is also important to take into account the integrated protection circuit IC power consumption, resistance to high voltage problems. Moreover, in order to power MOSFET’s Rds (on) in the charge current and discharge current when the effective application is required so that the impedance as low as possible, at present the impedance is about 20 ~ 30 m?, the overcurrent detection voltage can be so low.
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Vishay-Dale 4.7 ohm Surface Mount Thick Film Resistor 0805 5% 1/8W 200ppm CRCW0805 (Continuous strip of 200) Feature
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Vishay-Dale 4.7 ohm Surface Mount Thick Film Resistor 0805 5% 1/8W 200ppm CRCW0805 (Continuous strip of 200) Overview
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Vishay-Dale 4.7 ohm Surface Mount Thick Film Resistor 0805 5% 1/8W 200ppm CRCW0805 (Continuous strip of 200) Specifications
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Vishay-Beyschlag 1.07K ohm Surface Mount Thin Film Precision Resistor 0402 0.1% 1/16W 25ppm MCS0402 (Continuous strip of 100)
Vishay-Beyschlag 1.07K ohm Surface Mount Thin Film Precision Resistor 0402 0.1% 1/16W 25ppm MCS0402 (Continuous strip of 100) Feature
- Resistance: 1.07K ohms
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Vishay-Beyschlag 1.07K ohm Surface Mount Thin Film Precision Resistor 0402 0.1% 1/16W 25ppm MCS0402 (Continuous strip of 100) Overview
Vishay-Beyschlag 1.07K ohm Surface Mount Thin Film Precision Resistor 0402 0.1% 1/16W 25ppm MCS0402 100% TIin RoHS (Continuous strip of 100)
Vishay-Beyschlag 1.07K ohm Surface Mount Thin Film Precision Resistor 0402 0.1% 1/16W 25ppm MCS0402 (Continuous strip of 100) Specifications
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