In the previous article, we introduced the CR5218SC_5V1.0A_EE13 non-standard DEMO demo based on Sirida's main push for our friends. In this article, I will introduce the 12W charger solution, which is a charger with a full voltage output of 5V2.4A. Among them, the control IC adopts CR5215SG+CR40V20RSA which is mainly promoted by Siruida. So, what are the features of this program? Let's look down.

01. Prototype introduction

The test report is based on a charger prototype that can be applied to a wide input voltage range, output power 12W, and constant voltage output. The control IC adopts CR5215SG+CR40V20RSA, which is mainly promoted by Sirius.

Schematic diagram of CR5215SG+CR40V20RSA_5V2.4A engineering prototype


The CR5215SG is a high-performance offline PWM controller for low-power AC/DC chargers and power adapters. The chip adopts the topology of primary side detection and adjustment, so it does not need TL431 and optocoupler in application. The chip has two built-in constant current/constant voltage control modes.

In constant current control, the maximum output current and output power can be set by the current limiting resistor RS of the CS pin. In constant voltage control, the built-in constant voltage sampling circuit and high-precision error comparator reference voltage ensure the high performance and high precision of the chip. In addition, the built-in line loss compensation circuit ensures the output voltage accuracy from no-load to full-load conditions. The chip also has a very low quiescent current, and the standby power consumption of the chip is less than 75mW.

CR5215SG has designed a series of comprehensive protection measures against various faults, including cycle-by-cycle peak current limit, VDD overvoltage protection, FB open circuit protection, output short circuit protection, leading edge blanking, overtemperature protection, power supply clamp and undervoltage lockout function . It can be effectively protected under fault conditions such as FB pull-up resistor open circuit, FB pull-down resistor short circuit, output diode open circuit or short circuit, transformer winding short circuit, CS pin resistance open circuit, etc., making the chip more reliable.

Chip characteristics

● CR5215SG is built-in 700V power transistor, flyback QR primary control PWM power switch;

● Built-in soft start, built-in slope compensation circuit, built-in over-power compensation;

● Lower IC power consumption;

● With frequency jitter function, it has good EMI characteristics;

● Energy efficiency balance technology of multi-mode control, low standby and high efficiency to meet energy efficiency requirements;

● With "soft start, OCP, SCP, OTP, OVP automatic recovery and other protection functions;

● Simple circuit structure and less peripheral components, suitable for low-power AC/DC power adapters and chargers.

Basic application

●Low power power adapter

●Cell Phone Charger

●Christmas lights, LED driver

●Replaces linear regulators and RCCs

typical application

Pin arrangement

Pin description


Chip Features:

● 5V output synchronous rectifier chip, can work in DCM and QR mode;

● Simplify peripheral circuits;

● Lower operating current and higher system efficiency meet energy efficiency requirements.

Prototype PCBA size: W*L*H=30*41.5*15.4mm, it is a full voltage charger with 5V2.4A output. Under the condition that the AC100V meets the startup time, the standby power consumption of the AC264V prototype is only 56mW; it can meet the strictest "COC_V5_T2" energy efficiency standard when the full voltage is input; it meets the EMI requirements; the full voltage can achieve 5% voltage and current output accuracy.

The prototype has good constant voltage and constant current output effect; at the same time, it has various protection functions such as "soft start, output short circuit protection, OCP, SCP, OVP, OTP automatic recovery".

The transformer of the prototype adopts EF1510 thickened magnetic core (PC40 material). For the part of the winding process of the transformer, please refer to the detailed description later.

02. Prototype features

The following table shows the main characteristics of the engineering prototype, and the specific test methods are described in detail in Chapter 4.

2.1. Input characteristics:

2.2. Output characteristics (PCB END):

2.3. Machine parameters:

2.4. Protection function test:

2.5. Working environment:

2.6. Test equipment:

03. Prototype structure information

This section shows the circuit, layout structure, transformer structure and process of the engineering prototype.

3.1. Circuit schematic and BOM:

3.1.1 Schematic diagram:

3.1.2. Components list:

3.1.3. PCB wiring:

3.2. Transformer winding process:

3.2.1. Circuit diagram:

3.2.2. Specifications:

1) Frame: EF1510 magnetic core thickened, Ae=40mm²;

2) Material: TDK PC40 or equivalent;

3) N1, N2, N4, N5: 2UEW enameled wire; N3: three-layer insulated wire;

4) Magnetic core grounding Pin5;

5) Insulation tape: 3M900 or equivalent material, tape with a width of 6mm;

6) Primary winding inductance Lp: 1.0mH±5% (test condition: 0.3V, 10kHz);

7) The leakage inductance LLK: it is required to be controlled within 5% of the primary winding (test conditions: 0.3 V, 10kHz);

8) Withstand voltage test = 3.3KV 5mA 1Min;

9) Finished product requirements: immersion in water;

3.2.3. Transformer parameters:

04. Performance evaluation

This section tests the input part, output part, various protections and some timing sequences of the engineering prototype. The test methods and results are explained in detail below. From the test results, the following tests are all qualified and can meet the requirements of most customers.

4.1. Input characteristics:

This template has been tested under different input voltages (from 90V/60Hz to 264V/50Hz) and different load conditions (no load and full load) to obtain standby power consumption, efficiency and average efficiency.

Table 1 Standby power consumption (output with dummy load 1.8KΩ)

Table 2 Input characteristics under output 100% load

Table 3 Efficiency Test (PCB END)

4.2. Output characteristics:

4.2.1. Linear regulation and load regulation:

4.2.2. Output voltage ripple:

Note: Ripple and noise are tested on the PCB side. At the same time, a 0.1uF/50V ceramic capacitor and a 10uF/50V electrolytic capacitor are connected in parallel with the PCB side, and the bandwidth is limited to 20MHz.

R&N @ AC90V/60Hz,No Load

R&N @ AC90V/60Hz,100% Load

R&N @ AC264V/50Hz,No Load

R&N @ AC264V/50Hz,100% Load

4.3. Protection function:

Note: The following tests involve overcurrent protection and short circuit protection.

4.3.1. Overcurrent protection:

4.3.2. Short circuit protection:

4.4. Dynamic test:

Note: The output dynamic load current is set to 2.4A for 5ms/10ms, then 0A for 5ms/10ms and loops continuously, the rise/fall is set to 3A/uS.

AC90V @ 5ms

AC90V @ 10ms

AC264V @ 5ms

AC264V @ 10ms

4.5. System delay time test:

Note: AC terminal (green), VO output terminal (blue) waveform diagram.

[email protected] AC90V,100% Load

[email protected] AC264V,100% Load

[email protected] AC90V,100% Load

[email protected] AC264V,100% Load

[email protected] AC90V,No Load

[email protected] AC264V,No Load

4.6. IC temperature test data:

Under 40℃ environment, full load output test result

4.7. Other important waveform tests:

Note: DRAIN (green) and CS (blue) waveforms.

AC90/60Hz,100% Load

AC115/60Hz,100% load

AC230/50Hz,100% Load

AC264/50Hz,100% load

AC264/50Hz,Output Short

AC264/50Hz, Output diode

05. EMI evaluation test

Test Conditions:

Input: AC115V/50Hz, AC230V/50Hz;

Output load: 2.083Ω/50W;

Limit standard reference: EN55013, EN55022B.

AC115V/50Hz conduction L phase

AC115V/50Hz conduction N phase

AC115V/50Hz Radiation Test

AC230V/50Hz conduction L phase

AC230V/50Hz conduction N phase

AC230V/50Hz Radiation Test

Reviewing Editor Huang Haoyu

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