Self-Supplied Voltage Regulator Startup Circuit
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Solution Overview
Problem
Existing voltage regulators require a dedicated startup circuit that needs a voltage reference for initiation and does not account for process variations, limiting the output voltage range at low voltages and consuming unnecessary power.
Innovation Solution
A self-supplied voltage regulator circuit that uses a current comparison between the voltage regulator's current capability and the startup circuit's current to switch off the startup condition, eliminating the need for an external voltage reference and ensuring the startup circuit is always disconnected at the lowest possible output voltage, thereby reducing power consumption and expanding the regulator's low-voltage operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage reference is used for startup circuit initiation, then the startup circuit can be reliably activated, but the output voltage range is limited at the low voltage end and the circuit becomes dependent on process parameters
Solution Approach 1:
The voltage regulator supplies its own regulated voltage to the startup circuit, eliminating the need for external voltage references. The regulator's output voltage directly enables the startup circuit operation, making the system self-sufficient and expanding the low-voltage operating range while maintaining startup reliability
Solution Approach 2:
The invention changes the operating parameters by using the regulator's own output voltage as the enable voltage for the startup circuit. This dynamic parameter approach replaces fixed voltage references, allowing the circuit to adapt to different process conditions and achieve a wider output voltage range
2Reliability
If the startup circuit remains active to ensure reliable operation, then startup reliability is maintained, but power consumption increases unnecessarily
Solution Approach 1:
The startup circuit is activated only when needed - specifically when the regulator's output voltage is insufficient to maintain proper operation. Once the output voltage reaches the required level, the startup circuit automatically disables itself, eliminating unnecessary power consumption while ensuring reliable operation during the critical startup phase
Solution Approach 2:
The startup circuit operates periodically or transiently rather than continuously. It activates during startup conditions and automatically disables when the regulator reaches normal operation, creating an on-demand operation mode that reduces overall power consumption while maintaining reliability
3Reliability
If the startup switch-off voltage is chosen for worst case conditions, then startup is guaranteed under all conditions, but the output voltage range is limited at low voltages
Solution Approach 1:
The invention dynamically adjusts the startup switch-off voltage based on the regulator's actual output voltage rather than using a fixed worst-case threshold. This adaptive parameter selection allows the circuit to operate efficiently across a wider voltage range while still guaranteeing startup under all conditions
Solution Approach 2:
The startup circuit's switch-off voltage is made dynamic rather than static. It adapts to the regulator's output voltage in real-time, allowing optimal operation across varying conditions and expanding the low-voltage range while maintaining startup guarantees through feedback-based control
Data Source
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AI summary
A startup circuit for starting up a self-supplied voltage regulator which initiates startup by applying a voltage from a voltage supply to the startup circuit thus causing a voltage at an output node to rise. This rise will start the operation of the differential amplifier of the voltage regulator. When the voltage at the output node has reached the desired final output voltage, the startup circuit disconnects from the voltage regulator. The criterion for switching off the startup circuit is determined by a comparator which compares the output current capability of the voltage regulator with its output current plus the startup current. Inputs to the differential amplifier, such as the reference voltage, derive their power from the output node.