UVLO Circuit Digital Voltage Detection Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switching power supply systems with UVLO circuits face inflexibility in setting threshold voltages and hysteresis characteristics, and high power consumption due to current flow through voltage dividing circuits.
Innovation Solution
A UVLO circuit that detects input voltage as a digital signal for comparison with digital reference levels, allowing adjustable threshold voltages and hysteresis, and shuts off current paths during non-detection periods to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage dividing circuit with resistors is used to detect input voltage, then the UVLO circuit can compare voltage levels, but the circuit consumes high power due to continuous current flow
Solution Approach 1:
The patent implements periodic voltage detection by controlling the switching element to turn on only during detection periods and off during non-detection periods. This periodic operation allows the UVLO circuit to monitor input voltage at intervals rather than continuously, significantly reducing power consumption while maintaining adequate voltage detection capability for protecting against under-voltage conditions.
Solution Approach 2:
The patent extracts the essential function of voltage detection from a continuous operation and separates it into discrete detection events. By using a switching element to gate the voltage dividing circuit, only the necessary detection function is activated when needed, while power consumption is minimized during non-detection periods when the switching element is off.
2Ease of manufacture
If fixed resistor values are used in the voltage dividing circuit, then the circuit is simple to manufacture, but the threshold voltage and hysteresis characteristics cannot be adjusted flexibly
Solution Approach 1:
The patent transforms the static resistor values into dynamic, adjustable parameters by introducing switching elements that can selectively connect different resistor combinations. This allows the voltage dividing ratio to be changed dynamically based on desired threshold voltages and hysteresis characteristics, providing flexibility while maintaining a relatively simple circuit structure using standard resistor values.
Solution Approach 2:
The patent segments the voltage dividing circuit into multiple resistor pairs that can be selectively activated. Instead of using a single fixed resistor configuration, the circuit is divided into segments that can be combined in different ways by the switching element, enabling multiple threshold voltage settings and hysteresis characteristics from a single circuit topology.
3Reliability
If the UVLO circuit continuously monitors input voltage, then voltage protection is reliable, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring of the input voltage by controlling the switching element to activate the voltage dividing circuit only during detection periods. This periodic operation maintains reliable voltage protection by detecting under-voltage conditions when they occur, while significantly reducing power consumption compared to continuous monitoring.
Solution Approach 2:
The UVLO circuit uses feedback through the switching element control to determine when voltage detection is necessary. The circuit monitors voltage conditions and activates detection only when potentially problematic voltage levels are detected, rather than continuously operating at full power, thus balancing reliability with power efficiency.
Data Source
AI summary
A switching power supply system controlling switching operations of switching devices by a control circuit to convert an input voltage into a desired output voltage, the system being provided with a under voltage lock out circuit including: an input voltage detection unit detecting an input voltage and producing an input voltage digital signal corresponding to the input voltage Vin; and a voltage level comparison unit carrying out digital comparison of the input voltage digital signal with each of two voltage detection level data and outputting the results of the comparisons as an output signal, in which by changing voltage detection level data stored in two registers, desired voltage detection levels and hysteresis characteristic are easily actualized.