Circuit analysis of five car charger
Car charger should not only consider the actual demand of rechargeable lithium batteries (CV constant voltage, constant current CC, overvoltage protection OVP), but also take into account the on-board battery environment (transient voltage spikes, system switching noise interference, EMI etc.); therefore the power management IC car charger selection scheme must be satisfied with: high pressure, high efficiency, high reliability, low frequency (Design for EMI) switching power supply chip; popular talk is "rugged".
Common car charging scheme is as follows:
1 single chip 34063 to achieve the final car charging program schematic
Advantages: low cost;
Shortcomings:
(1) poor reliability, single function; no over temperature protection, short circuit protection and other security measures;
(2) although the output voltage is DC, but the control of the current output constant current charging mode for maximum switching current peak limit, the accuracy is not high enough;
(3) the 34063 1.5A PWM+PFM switch current mode (no error amplifier), the ripple of the output DC voltage of the current car charging scheme is relatively large, not pure; output current capability is very limited; (low-end car charger scheme between 300ma~600ma in common)
2.34063+NPN (NMOS) to achieve the expansion of the car charging program schematic
Advantages: on the basis of the "1" program to expand the flow to meet the growing demand for charging current capacity;
Disadvantages: similar deficiencies exist in the "1" scheme;
3 Schematic diagram of the 2576+358+ regulator tube
Advantage：
(1) the 2576 built-in overcurrent protection, over temperature protection and other security measures, combined with the 358 (Shuang Yunfang) to achieve the output voltage CV, current CC, OVP overvoltage protection function; realize the lithium battery reliability and safety, improve the charging scheme;
(2) because the is a fixed 52K PWM converter, the EMI design of the car is relatively easy;
(3) since 2576 and 358 are made of 40V high voltage bipolar technology, more robust";
(4) this kind of scheme is commonly used in 0.8A ~ 1.5A or so;
Shortcomings:
(1) the system is complex and the cost is high;
(2) CC with constant current and overvoltage protection OVP through the 358 output to control 2576 EN to achieve, so the charging current ripple is relatively large, the response speed of CC and OVP is not fast enough (by switching 2576 is working to achieve);
4.XLSEMI design of a single car charging IC XL4002 schematic
Advantages: in addition to the corresponding advantages of the scheme, there are 3:
(1) a fully integrated solution for vehicle charging, low cost and high reliability;
(2) IC internal CV, CC, OVP are controlled by the PWM; therefore, the output voltage, output current, output over-voltage protection of higher accuracy, fast response;
(3) core dragon provides charging current between 0A ~ 3A charge a series of cost-effective products;
Shortcomings:
(1) low operating frequency (52KHz), large external inductor (100uH);
(2) peripheral component complex, external Schottky diode;
(3) low efficiency ((90%))
5.5202 single car charging IC program
Advantages: in addition to the corresponding advantages of the scheme, there are 34:
(1) the operating frequency is high (340KHz), the external inductance is small (10uH);
(2) peripheral components are simple, built in Schottky diode;
(3) built in switch MOSFET small internal resistance (130m) high efficiency (> 90%)
Edit comment: This paper introduces several car charger charging circuit, monolithic 34063 scheme of low cost; 34063+NPN (NMOS) to realize car charge expansion flow can meet the charging current capacity of growing demand; 2576+358+ regulator of the scheme of lithium battery is reliable and safe, improve the charging scheme.
