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Common Car Charging Solution
- May 04, 2018 -

Conventionally used in car battery (car 12V, truck 24V) car charger, used in a variety of portable, handheld devices, lithium battery charging areas, such as: mobile phones (phone car charger), PDA, GPS, etc.;

Car charger must consider the actual demand of lithium battery charging (constant voltage CV, constant current CC, OVP overvoltage protection), but also take into account the harsh environment of the vehicle battery (transient spike voltage, system switching noise interference, EMI, etc.); The power management IC selected by the vehicle charging scheme must satisfy the requirements of high-voltage, high-efficiency, high-reliability, and low-frequency (in favor of EMI design) switching power supply chips.

The common car charging plan is as follows:

1. Low-end vehicle charging solution with single chip 34063

Advantages:: low cost;

Disadvantages: (1) poor reliability, single function; no over temperature protection, short circuit protection and other safety measures;

(2) Although the output is a DC voltage, the way to control the output constant current charging current is the maximum limit of the switching current and the accuracy is not high enough;

(3) Because the 34063 is 1.5A switching current PWM + PFM mode (without internal error amplifier), the DC voltage and current output of the vehicle charging scheme is relatively large and pure; the output current capability is also very limited; (commonly seen in 300ma~ Low-end car charging scheme between 600ma)

2. 34063+NPN (NMOS) vehicle charging solution for expanding flow

Advantages: Expand the flow based on the [1] solution to meet the growing demand for charge current capability;

Disadvantages: There are also similar shortcomings in the [1] scheme;

3. Use 2576+358+ Regulator Solution

Advantages: (1) Because 2576 built-in over-current protection, over-temperature protection and other safety measures, combined with 358 (double op amp) to achieve the output of constant voltage CV, constant current CC, overvoltage protection OVP and other functions; to achieve a reliable, safe, Perfect lithium battery charging scheme;

(2) Since the 2576 is a fixed 52K PWM converter, the EMI design of the vehicle charger is relatively easy;

(3) Since 2576 and 358 are all manufactured with 40V high voltage bipolar process, they are more "skinny";

(4) This scheme is commonly used in car chargers of 0.8A ~ 1.5A;

Disadvantages: (1) The system is relatively complex and costly;

(2) Constant current CC and overvoltage protection OVP is achieved by controlling the EN of the 2576 through the output of the 358, so the charging current has a relatively large ripple, and the response speeds of the CC and the OVP are not fast enough (whether by switching 2576 is Work to achieve);

4. XLSEMI Design Single-Chip Charger IC XL4002

Advantages: In addition to the corresponding advantages of the [3] scheme, there are:

(1) A fully integrated solution dedicated to vehicle charging, with low system cost and high reliability;

(2) IC internal CV, CC, OVP are all controlled by PWM; therefore, the output voltage, output current, and output overvoltage protection are more accurate and the response speed is fast;

Disadvantages: (1) Low operating frequency (52KHz), large external inductor (100uH);

(2) Complex external components, external Schottky diodes;

(3) Low work efficiency (90%)

5. 5202 Single Car Charger IC

Advantages: In addition to the corresponding advantages of the [34] scheme, there are:

(1) High operating frequency (340KHz), small external inductance (10uH);

(2) Simple external components, built-in Schottky diodes;

(3) Built-in switching MOSFET has small internal resistance (<130mΩ) and high working efficiency (>90%)