会社のニュース Optimizing Power Efficiency in Portable Devices with 0.42-inch PMOLED Technology

The Power Challenge in Portable Electronics
As portable medical devices, wearables, and handheld instruments become increasingly sophisticated, power management emerges as the critical design constraint. Display subsystems often represent significant power consumers, making OLED technology selection crucial for achieving optimal battery life.

Power Consumption Analysis: SFTOS042XZ-7110AN
The SFTOS042XZ-7110AN PMOLED module from Saef Technology Limited incorporates multiple power-saving features essential for portable applications:

Current Consumption Breakdown

• Active Mode: 180μA typical (VDD), 22mA typical (VBAT with internal DC/DC)

• Sleep Mode: 1μA typical (VDD), 2μA typical (VCC)

• Display OFF Current: Minimal leakage current with proper shutdown sequencing

Power Supply Configurations
Engineers can select between two primary power configurations based on application requirements:

1. Internal DC/DC Converter (VBAT = 3.5V-4.2V)

   • Ideal for battery-powered applications

   • Integrated charge pump eliminates external boost converter

   • Components: C1-C2 (0.1μF, 4.7μF), C3-C4 (2.2μF, 4.7μF)

2. External VCC Supply (8.5V-9.5V)

   • Suitable for line-powered applications

   • Bypasses internal DC/DC for slightly improved efficiency

Software-Controlled Power Management
The SSD1315 controller enables sophisticated power management through command interface:

// Enter sleep mode sequence
write_cmd(0xAE); // Display OFF
write_cmd(0x8D); // Charge pump setting
write_cmd(0x10); // Disable charge pump
// Power down VBAT

// Wake from sleep mode
// Power up VBAT
write_cmd(0x8D); // Charge pump setting
write_cmd(0x14); // Enable charge pump
write_cmd(0xAF); // Display ON

Interface Selection Impact on Power Consumption
The dual-interface capability allows optimization based on host microcontroller:

• I²C Interface: Lower pin count, suitable for simple command structures

• 4-Wire SPI: Higher data throughput, potentially reducing active communication time

Thermal Considerations for Battery Safety
Efficient power management extends beyond battery life to thermal performance. The display's wide operating temperature range (-40°C to +85°C) ensures reliability even in challenging environmental conditions.

Design Recommendations for Maximum Efficiency

• Implement proper power sequencing during startup/shutdown

• Utilize sleep modes during inactive periods

• Optimize display refresh rates based on application needs

• Select appropriate interface based on data throughput requirements

Real-World Battery Life Calculations
For a typical 500mAh Li-ion battery:

• Continuous operation: ~22 hours (22mA average)

• Intermittent use with sleep modes: Weeks to months of operation

Conclusion
The SFTOS042XZ-7110AN provides portable device designers with a power-optimized display solution without compromising optical performance. For comprehensive technical details, consult the complete SFTOS042XZ-7110AN DATASHEET.pdf  document.