Switch-mode Power Supply Charging Current Source Shutdown
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Solution Overview
Problem
Conventional switch-mode power supply timers fail to completely shut down the internal charging current source during standby mode, leading to increased power consumption, and require additional pins for mode-switching functions, which increases the cost of integrated circuits.
Innovation Solution
A switch-mode power supply configuration that includes a converter, controller, and a charging current source with a multi-functional pin generating a frequency signal based on the input voltage or zero voltage, a logic circuit generating control signals to indicate operation modes, and two current sources that generate output currents proportional to the input voltage, allowing for efficient power management and reduced pin requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the charging current source remains active during standby mode, then the timer can quickly resume operation, but power consumption increases
Solution Approach 1:
The charging current source is controlled to operate periodically rather than continuously. During standby mode, the current source is completely shut down and only activated when needed for timing operations, achieving both low power consumption and quick resume capability through on-demand operation
2Adaptability or versatility
If additional pins are added for mode-switching functions, then the controller can support multiple operation modes, but the IC cost increases
Solution Approach 1:
The multi-functional pin can operate in different modes depending on the configuration. It can serve as an external clock input pin or function as the multi-functional pin for mode selection, eliminating the need for separate dedicated pins for each function and reducing overall pin count while maintaining versatility
Data Source
AI summary
A switch-mode power supply includes a converter, a controller and a charging current. The charging current includes a logic circuit, a first current source and a second current source, to generate a charging current proportional to an input voltage of the switch-mode power supply, and also to generate a logic control signal indicative of either of two operation modes.