1. Problem Description
When using the KT148A serial version voice chip for music playback, the microcontroller (MCU) malfunctions immediately. Measurements reveal significant power supply fluctuations during music playback initiation. According to the manual, this is likely caused by insufficient drive capability. However, the same power supply works normally when connected to the official test board.
2. Analysis
The root cause is clearly power supply instability - a common issue resolvable through basic circuit design principles.
Key Considerations:
- Power Supply Configurations: The KT148A chip has two power supply configurations (refer to power supply notes in the upper-right corner of the figure).
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Current Consumption Factors:
- Speaker impedance and power rating (larger speakers → higher current draw)
- Playback volume (higher volume → greater power consumption)
- Maximum drive capability: Approximately 200 mA
Reference: Official test board minimum system schematic
3. Solutions and Recommendations
PCB Design Improvements:
- Use thicker power traces to reduce voltage drop
- Keep KT148A power traces as short as possible to minimize resistance and interference
Power Supply Enhancements:
- Add a decoupling capacitor at KT148A power input:
- Recommended: Electrolytic capacitor (e.g., 47μF/16V) or similar
Power Source Requirements:
- Ensure stable and robust power source
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Avoid using:
- Long/thin Dupont jumper wires
- Weak power supplies
- Such setups cause severe voltage fluctuations leading to chip resets or MCU abnormalities
Note: These are fundamental power design principles. Review basic circuit design if necessary.
Additional Recommendation:
- If experiencing voice data download issues, use the official full-featured download board for testing (refer to diagram below).
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