45W Bidirectional Fast Charging Power Bank Mainboard/Module
The 45W Bidirectional Fast Charging Power Bank Mainboard/Module (hereinafter referred to as "45W Module") is the best-selling "sweet spot power" in the PD3.0 era: it can not only drive MacBook Air, iPad Pro, and Switch at full speed with 20V/2.25A, but also self-charge at 45W at high speed, regaining 60% of power in 30 minutes, perfectly covering the 10000-20000 mAh thin and light travel scenarios. The following text explains everything from the chip level to the mass production level in one go, which can be directly used as a technical blog, detail page or project initiation report.
I. Comparison and Selection of Chip Solutions
Model | Power Tube Integration | Efficiency | Package | Features | Reference Price |
|---|
IP5356 (Injoinic) | Built-in | 95% | QFN-32 | Single-inductor Buck-Boost, simplest peripheral circuit, open SDK | ¥3.8 |
SC8815 (Southchip) | External | 96% | QFN-40 | Separate Buck-Boost + PD3.0 PHY, externally compensable loop | ¥4.2 |
SW2505 (Sinowealth) | External | 95% | QFN-32 | Dual PD PHY, supports dual C-port 45W blind insertion | ¥4.5 |
Conclusion: Choose IP5356 for the simplest BOM and shortest development cycle; choose SC8815 if external MOS is needed for larger current or metal case heat dissipation; choose SW2505 for dual C-port independent 45W blind insertion.
II. Hardware Architecture (Taking IP5356 as an Example)
Single-inductor Buck-Boost
External 4 × 30V/5mΩ MOS + 4.7µH/6mm alloy inductor, achieving a peak efficiency of 95% (12V→20V segment).
Switching frequency is 500kHz, inductor ripple ≤ 30%, full-load MOS temperature rise is 35℃ (with 3mm aluminum sheet).
Protocol/Protection
On-chip integration of PD3.0, QC4+, PPS, FCP, SCP, AFC, Apple 2.4A, BC1.2 DCP, automatically requests the highest PDO.
12-bit ADC polls VIN, VOUT, IBAT, VBAT; NTC temperature loop reduces power at 75℃ and shuts down hardware at 85℃.
Battery Management
Supports 3-5 series ternary lithium/lithium iron phosphate batteries, charging voltage is software-selectable at 4.2V/4.35V/3.6V; built-in 50mA balancing with ±15mV accuracy.
Charging current is adjustable from 0.3-5A, and discharge current is up to 15A (limited by MOS and inductor Isat).
Interface Configuration
2C1A classic layout: C1/C2 blind insertion 45W, A port 22.5W SCP; simultaneous three-port output 45W + 45W + 18W ≈ 108W.
On-board 0.96-inch IPS color screen or 4 LED power lights, reads IP5356 registers via I²C to realize 1% accuracy display of power, current, voltage and temperature.
III. Key Performance Test Results
Item | Specification | Remarks |
|---|
Input Range | 5-20V | Compatible with any 18W-65W PD adapter |
Output Range | 3.3-20V | PPS 3.3-11V/4A, fixed PDO 5/9/12/15/20V |
Peak Efficiency | 95% | 15V→20V segment, load 30-45W |
Standby Power Consumption | 3µA | Ship-mode, wake up by long pressing the key for 2s |
Temperature Protection | 85℃ | Can be downregulated by software |
Inductor Peak Current | 20A | Select 4.7µH, Isat ≥ 25A |
PCB Dimensions | 28mm × 48mm × 1.2mm | Double-layer board, single-sided SMT |
IV. Design/Mass Production Guidelines
Inductor Selection
4.7µH, DCR ≤ 4mΩ, Isat ≥ 25A, package 6mm × 6mm; shielded alloy inductor can reduce EMI by 3dB.
MOS Selection
30V/5mΩ grade, Ciss ≤ 800pC, package DFN3×3; two parallel connections can disperse heat sources.
PCB Layout
Power loop ≤ 4mm, Kelvin sampling adopts differential routing, SW node exposes copper and adds tin + gluing to reduce spikes and temperature rise.
Heat Dissipation Design
When 45W is fully loaded, the power consumption of MOS + inductor is about 2W, which can be achieved with a 3mm aluminum heat sink or 0.2mm graphite sheet + thermal conductive adhesive; metal shell can reduce the temperature by another 5℃.
Certification Strategy
PD3.0 certification requires 20V short circuit, overshoot, and loop stability tests; 0.15mm safety spacing is reserved on the board, and VBUS traces are 1oz copper.
Customer Lock-in & Customization
IP5356 opens I²C for voltage/current adjustment and light effect adjustment, supporting secondary development; Sinowealth SW2505 integrates dual PD PHY and screen driver, reducing the development cycle from 4 weeks to 2 weeks.
