To design a 20W SVOOC + QC (Quick Charge) mobile charger solution, we would need to integrate both SVOOC (SuperVOOC), a fast-charging protocol developed by OPPO, and QC (Quick Charge), developed by Qualcomm. These two standards allow devices to charge faster, but they work differently. Here’s an overview of the solution:
1. Charger Input Specifications
- AC Input: 100-240V, 50-60Hz (typical for universal use)
- Power Output: 20W
- Efficiency: Must comply with regulatory standards (over 85% efficiency is good)
2. SuperVOOC (SVOOC) Specifications
- Voltage/Current: SVOOC typically works at 5V/4A to provide up to 20W of power.
- Communication: SVOOC requires a communication link between the charger and the phone to ensure voltage and current regulation, often implemented via a smart MCU inside the charger.
- Temperature Control: SuperVOOC systems monitor temperature to avoid overheating. Implementing a thermistor or NTC circuit might be necessary.
3. Quick Charge (QC) Specifications
- QC Version: QC 3.0 or QC 4.0 could be used, both of which support 20W charging.
- QC 3.0: Supports 3.6V to 20V at variable current up to 3A, dynamically adjusting voltage based on device demand.
- QC 4.0+: Compatible with USB-PD (Power Delivery), allowing more flexible voltage and current regulation, offering both faster charging and lower heat generation.
4. Power Management ICs (PMIC)
- SVOOC PMIC: You will need a dedicated SVOOC controller IC such as the PFC (Power Factor Correction) + PWM controller, which handles the fast charge requirements.
- QC PMIC: For QC functionality, you can use Qualcomm-certified ICs like the ON Semiconductor NCP4371 (for QC 3.0) or NCP1568 (for QC 4.0).
5. Output Power Design
For dual-standard chargers, the circuit should safely switch between SVOOC and QC, depending on the device. This can be done via:
- Auto-detection Circuit: Use a negotiation protocol to detect if the connected device supports SVOOC or QC.
- Voltage Regulation: Depending on the protocol, the charger needs to supply the correct voltage (e.g., 5V for SVOOC and a range of 3.6V to 20V for QC).
6. Safety Features
- Over-voltage/over-current protection: Essential to protect both the charger and the device.
- Thermal shutdown: Important for preventing overheating, especially when fast-charging.
- Short-circuit protection: To avoid any damage to the charger in case of a fault.
7. Design Components
- Transformer: Should be designed for high-frequency operation to ensure efficiency.
- Rectifier: Fast recovery rectifiers for efficient AC-DC conversion.
- MCU: For communication between the charger and the device for both SVOOC and QC protocols.
- Inductors/Capacitors: To stabilize the output voltage and current.
8. Cable Compatibility
- USB-C or Micro-USB: Depending on the devices you’re targeting, USB-C would be ideal due to its higher power delivery capacity and future-proofing.