Charge Pump Circuit for Load Switch Control
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Solution Overview
Problem
Switched mode power supplies lack efficient control mechanisms for managing load disconnection and connection, particularly in USB-based chargers, which can lead to inefficiencies and potential damage to connected devices due to inadequate voltage regulation and switch control.
Innovation Solution
A secondary side controller comprising a first semiconductor die with an integrated circuit and a second semiconductor die with a charge pump, where the load connection signal controls the generation and amplitude of the switch signal for an NMOS-based load disconnection switch, enabling precise voltage control and efficient connection or disconnection of the power supply to a load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a load disconnection switch is added to control connection/disconnection of the power supply output, then power delivery efficiency and device safety are improved, but the circuit complexity and control difficulty increase
Solution Approach 1:
The patent introduces an intermediary control circuit that includes a signal generator producing a load connection signal, which is then processed through a charge pump to generate the appropriate gate drive signal for the load disconnection switch. This intermediary control mechanism enables precise control of the power delivery while maintaining circuit modularity and managing complexity through functional separation.
2Manufacturing precision
If voltage regulation is implemented through a controlled switch, then power delivery precision and device safety are improved, but the control mechanism complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the load connection signal is generated based on detection of the actual connection state between the power supply output and the load. The signal generator monitors the connection status and adjusts the control signal accordingly, ensuring precise voltage regulation while preventing overvoltage conditions that could damage connected devices.
Solution Approach 2:
The charge pump circuit serves as an intermediary component that converts the load connection signal into the appropriate voltage level for controlling the load disconnection switch gate. This intermediary stage enables precise voltage regulation by decoupling the control logic from the power switching operation, managing complexity through functional separation.
3Measurement precision
If a charge pump is used to generate the switch signal voltage, then voltage control precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a charge pump circuit that dynamically adjusts the gate drive voltage based on the amplitude of the load connection signal. By changing the voltage parameter in response to connection status, the system achieves precise control of the load disconnection switch while enabling the switch to handle higher voltage requirements such as those in USB-PD protocols. This parameter-based control approach balances precision requirements with manageable device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides efficient voltage regulation and safe operation of USB-based chargers by ensuring the load is properly connected or disconnected, preventing damage and optimizing power delivery, with the ability to handle higher voltage requirements such as those in USB-PD protocols.
Implementation Method 1
the charge pump is configured to apply a voltage derived from the amplitude of the load connection signal to the at least one capacitor in accordance with the pulses
Data Source
AI summary
A secondary side controller for a switched mode power supply, the controller comprisinga first semiconductor die comprising an integrated circuit configured to provide a load connection signal;a second semiconductor die, packaged with the first semiconductor die, comprising a charge pump configured to, in response to the load connection signal received from the integrated circuit of the first semiconductor die, provide a switch signal for control of a load connection switch that controls whether or not the switched mode power supply is electrically connected to a load;wherein the presence or absence of the load connection signal is configured to control whether or not the charge pump generates the switch signal and the amplitude of the load connection signal is configured to control the voltage of the switch signal.