DC-DC Converter Pin Lift Detection With Low Quiescent Current
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Solution Overview
Problem
Existing DC-DC converters face damage due to pin lift conditions without effective detection methods that do not impact efficiency and require additional pins.
Innovation Solution
A pin lift detection circuit for DC-DC converters, comprising a current source, resistive divider, amplifier, comparator, digital filter, and timer circuit, which detects pin disconnections and controls the converter to prevent damage by disabling switches and reducing quiescent current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin lift detection circuit is added to detect disconnections, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into existing circuit elements: the detection circuit uses existing switches (HS switch, LS switch), current sources, and control circuits already present in the DC-DC converter. The pin lift detection is merged with the existing power conversion circuitry rather than being a separate independent system, thereby improving reliability without proportionally increasing overall device complexity.
Solution Approach 2:
Existing circuit components are made multi-functional: the control circuit not only controls the switching operation for power conversion but also detects pin lift conditions. The switches serve both power conversion purposes and detection purposes. This multi-functionality allows the system to gain detection capability without adding dedicated single-purpose components.
2Measurement precision
If detection circuit components are added, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the control circuit continuously monitors the state of electrical terminals and adjusts its operation accordingly. When a pin lift condition is detected, the control circuit receives feedback and responds by disabling the switches. This feedback-based approach enables precise detection of pin disconnections using existing circuit elements without requiring complex additional measurement infrastructure.
3Reliability
If additional detection components are added, then reliability is improved, but quiescent current increases
Solution Approach 1:
The detection operation is performed periodically or on-demand rather than continuously. The control circuit enables the switch and activates detection only when needed (e.g., when changes in terminal voltage are detected), rather than maintaining constant detection activity. This periodic action reduces the average quiescent current consumption while still providing reliable pin lift detection capability when required.
Data Source
AI summary
Embodiments of pin lift detection circuit for a direct current DC-DC converter and DC-DC converters are disclosed. In an embodiment, a pin lift detection circuit for a DC-DC converter includes a current source, a switch connecting the current source to an electrical terminal of the DC-DC converter, a resistive divider connected to the switch and to the electrical terminal of the DC-DC converter, an amplifier connected to the resistive divider, a comparator connected to the amplifier and to the resistive divider, a digital filter connected to the comparator and configured to generate a flag signal in response to a disconnection between the electrical terminal of the DC-DC converter and a load of the DC-DC converter, and a timer circuit configured to generate control signals for the switch, the comparator, and the digital filter.