Charge Pump Gate Drive Circuit Reducing Switch Impedance
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Solution Overview
Problem
Charge pumps used in portable devices face inefficiencies in power consumption and output voltage due to high on-resistance of MOS switches, which also lead to increased circuit area and costs, especially when converting a single battery voltage to multiple required voltages.
Innovation Solution
A charge pump design that increases the gate-to-source voltage of MOS switches using dynamic voltage within the circuit, reducing switch impedance and improving power efficiency, output voltage, and integrated circuit area efficiency without requiring extra power supply circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the gate-to-source voltage of MOS switches is increased using dynamic voltage within the circuit, then power efficiency and output voltage are improved, but circuit complexity increases
Solution Approach 1:
The charge pump circuit generates its own boosted gate voltage dynamically during operation using its internal pump capacitors and switches. The circuit serves itself by utilizing its own operating voltages to create the enhanced gate drive needed for low-impedance switches, eliminating the need for external voltage boost circuits or additional power supply networks.
Solution Approach 2:
The gate voltage is not fixed but dynamically generated and adjusted during the charge pump's operation cycles. The boosted gate voltage is created on-demand using the pump capacitors that naturally oscillate during charging and discharging phases, allowing the circuit to adapt its gate drive voltage to its operational state without requiring static external voltage sources.
2Loss of energy
If MOS switches with higher gate-to-source voltage are used, then switch impedance is reduced and power efficiency is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The pump capacitors in the charge pump circuit serve multiple functions: they perform the primary voltage multiplication task of the charge pump while simultaneously acting as energy storage elements that provide the boosted gate voltage. This multi-functionality eliminates the need for separate voltage generation circuits, simplifying manufacturing while achieving low-impedance switches through enhanced gate drive.
Solution Approach 2:
The circuit dynamically changes the gate voltage parameter from the standard supply voltage to a boosted voltage level during specific operational phases. By modulating the gate voltage parameter using the naturally oscillating pump capacitors, the switches achieve lower impedance and improved power efficiency without requiring different transistor devices or complex manufacturing processes.
3Area of stationary object
If dynamic voltage within the circuit is used to increase gate-to-source voltage, then integrated circuit area is reduced, but output voltage stability may be affected
Solution Approach 1:
The charge pump operates in continuous cyclic phases of charging and discharging, with the pump capacitors constantly oscillating between voltage states. This continuous operation ensures that the boosted gate voltage is consistently available during each cycle, maintaining steady switch performance and stable output voltage without interruption or significant variation.
Solution Approach 2:
The charge pump circuit inherently provides feedback through its oscillating operation, where the output voltage level influences the charging and discharging timing of the pump capacitors. This self-regulating feedback mechanism ensures that the dynamic gate voltage remains appropriately synchronized with the output requirements, maintaining voltage stability despite the dynamic nature of the gate drive.
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
The solution effectively reduces power consumption and enhances output voltage levels while minimizing circuit area and costs by increasing the gate-to-source voltage of switches, improving overall power and area efficiency in charge pumps.
Implementation Method 1
a pump capacitor (10), a switching module (12) coupled to a first terminal of the pump capacitor (10)
Implementation Method 2
The first switch (14) is coupled between a second terminal of the pump capacitor (10) and a supply voltage (VDD)
Data Source
AI summary
The present invention relates to a charge pump capable of enhancing power efficiency and output voltage, which comprises a pump capacitor, a switching module, a first switch, a first buffer, a first switch, and an output capacitor. The switching module is coupled to a first terminal of the pump capacitor. The first switch is coupled between a second terminal of the pump capacitor and a supply voltage. The first buffer receives a first input signal and produces a control signal for controlling the first switch to turn on or cut off. The level of the first input signal ranges between a first voltage and a second voltage, wherein the first and the second voltages are related to the gate voltage of the first switch. The gate voltage of the first switch is a multiple, which is greater than one, of the supply voltage. Thereby, the impedance of the switch is reduced, and hence the power efficiency of the charge pump, the output voltage level, and the area efficiency of integrated circuits are improved.