Dual-LDO Power Supply Circuit for Wide-Range IoT Voltage Control
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Solution Overview
Problem
Existing power supply circuits for devices like lithium-ion batteries struggle to operate efficiently above 3.6V, leading to increased complexity, semiconductor area occupancy, cost, and power consumption, making them unsuitable for low-power IoT applications.
Innovation Solution
A dual-LDO architecture with a control feature that allows changing MCU power modes, starting at 1.8V to prevent damage and reprogramming up to 3.3V, enabling operation up to 4.5V with reduced semiconductor area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-voltage circuits are used to operate above 3.6V, then the operating voltage range is extended, but the device complexity increases
Solution Approach 1:
The power supply circuit is divided into two separate LDO regulators: a first LDO for low-voltage operation (1.8V-3.6V) and a second LDO for high-voltage operation (3.6V-4.5V). This segmentation allows each regulator to be optimized for its specific voltage range, avoiding the need for a single complex high-voltage circuit while extending the overall operating range.
Solution Approach 2:
The system dynamically switches between the first and second LDO regulators based on the operating voltage requirements. A control mechanism monitors the voltage and activates the appropriate regulator, enabling the device to adapt to different voltage conditions without requiring a permanently complex high-voltage circuit architecture.
2Adaptability or versatility
If high-voltage circuits are used to operate above 3.6V, then the operating voltage range is extended, but the semiconductor area occupancy increases
Solution Approach 1:
By segmenting the power supply into two specialized LDO regulators rather than using a single high-voltage circuit, the semiconductor area is optimized. Each LDO is designed for its specific voltage range, resulting in more efficient area utilization compared to a general-purpose high-voltage circuit that would require larger safety margins and protective structures.
3Adaptability or versatility
If high-voltage circuits are used to operate above 3.6V, then the operating voltage range is extended, but the power consumption increases
Solution Approach 1:
The system dynamically selects the appropriate LDO regulator based on the current operating voltage, ensuring optimal power efficiency. The first LDO operates efficiently in the 1.8V-3.6V range while the second LDO handles 3.6V-4.5V, avoiding the excessive power consumption that would result from using a single high-voltage circuit across all operating conditions.
4Adaptability or versatility
If voltage is increased up to 4.5V, then the operating range is extended, but the risk of damage to external devices increases
Solution Approach 1:
The power supply is segmented into two regulated outputs: a first regulated voltage (1.8V-3.6V) safe for external devices and a second regulated voltage (3.6V-4.5V) for internal high-voltage operation. This segmentation ensures that external devices receive protected voltage levels while the system can still utilize higher voltages internally.
Solution Approach 2:
The first LDO regulator acts as an intermediary between the high-voltage source and external devices, providing voltage regulation and protection. It mediates the voltage level to ensure external devices receive safe operating voltages while the system can access higher voltages through the second LDO when needed.
Data Source
AI summary
A voltage regulator is embedded in a circuit intermediate a first node (coupled to a battery) and a second node (supplying power to an external memory). The voltage regulator is activatable in a first mode of operation for startup during which an voltage is applied to the second node that increases towards a supply threshold. In response to the voltage at the second node reaching the supply threshold, the voltage regulator transitions to a second mode of operation where a programmable regulated voltage (higher than the supply threshold) is applied to the second node. In response to receipt of a low-power operation request, a first high-drive regulator circuitry is deactivated and a second low-power regulator circuitry is activated to provide a third mode of operation at low power.