Power Supply Circuit with Control Logic for Continuous Bus and Battery Power
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Solution Overview
Problem
Existing power supply circuits for portable devices, such as MD players, face inefficiencies in power consumption due to voltage drops between power sources and inability to ensure continuous power supply when one power source is cut off, especially when operated by CPU-controlled switch devices.
Innovation Solution
A power supply circuit with a control circuit that includes a first and second switch device, a power synthesizing circuit, and voltage detection units to generate and manage power from both battery and bus sources, ensuring continuous power supply by selecting the appropriate power source and controlling switch devices based on detected voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diodes are used to combine power from battery and communication cable, then power can be supplied to CPU and power load, but voltage drop occurs between anode and cathode of the diodes and cutting of one power supply cannot be ensured
Solution Approach 1:
The patent introduces a control circuit as an intermediary between the power sources (battery and communication cable) and the load. This control circuit actively manages power distribution using switch devices controlled by detection circuits, replacing the passive diode-based power combining approach. The intermediary control circuit enables precise control over power flow, ensuring reliable power supply continuity while minimizing energy losses through optimized switching operations.
2Ease of operation
If CPU controls switch device to select power source, then power can be selectively supplied to CPU and power load, but when CPU is operated by power from external device, unplugging communication cable interrupts power to CPU and switch device cannot be controlled
Solution Approach 1:
The patent segments the power management system into distinct functional modules: a control circuit that operates independently, detection circuits for monitoring power source status, and switch devices for power routing. This segmentation allows the control circuit to autonomously manage power source selection based on detection signals, ensuring reliable power supply stability even when the CPU's power source changes or the communication cable is unplugged.
Solution Approach 2:
The patent implements a feedback mechanism where detection circuits continuously monitor the status of power sources and generate detection signals. These signals are fed back to the control circuit, which automatically adjusts the switching operations to maintain stable power supply. This feedback loop ensures that power source selection and supply stability are maintained dynamically without requiring direct CPU intervention during power transitions.
3Ease of operation
If switch device is controlled during startup when no power is supplied to CPU, then power source selection should be possible, but control cannot be executed without power to CPU
Solution Approach 1:
The patent implements preliminary action by enabling the control circuit to operate independently of the CPU during startup. The control circuit uses detection circuits to monitor power source availability and pre-configures the switch devices to establish proper power routing before the CPU becomes operational. This preliminary power management action ensures that power source selection is accomplished during startup without requiring CPU power or control.
Data Source
AI summary
A control circuit for a power supply circuit that selects an appropriate power source to continuously supply power. The control circuit includes a power synthesizing circuit for generating synthesized power by synthesizing a first power supplied from a regulator and a second power supplied from a regulator, or battery power and bus power, so that each circuit of the control circuit is operated by the synthesized power. Operation of the control circuit is enabled even if the supply of one power is stopped. The first switch device and the second switch device are controlled to select the appropriate power source in accordance with the currently supplied power so that power is continuously supplied.