Startup Regulator Circuit With Charge Pump Gate Pull-Up
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Solution Overview
Problem
Conventional high-voltage startup regulators face limitations in power consumption, application input range, and cost, particularly in low-power applications where achieving a trade-off between minimum resistance value for the pull-up resistor and minimum high-voltage input is critical.
Innovation Solution
The implementation of a circuit that includes a charge pump to sustain the gate leakage current, an electronic switch interposed between the gate and the pull-up resistor, and a comparator to control the switch, allowing for efficient gate pull-up and reduced voltage drop on the pull-up resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bypass transistor with gate leakage is used in conventional high-voltage startup regulators, then the solution is cost-effective, but power consumption increases and the minimum resistance value for the pull-up resistor is constrained
Solution Approach 1:
The charge pump is activated in advance to charge the capacitor before the bypass transistor needs to operate. This preliminary charging action stores energy that can be used to compensate for gate leakage current, reducing the continuous power consumption requirement of the pull-up resistor while maintaining cost-effectiveness of using a standard bypass transistor with gate leakage
Solution Approach 2:
The invention changes the operating parameters by introducing a dynamic charging mechanism. The capacitor voltage builds up over time according to the charging current from the charge pump, allowing the system to operate with lower pull-up resistor values without excessive power consumption. This parameter change enables both cost-effectiveness and reduced power consumption
2Ease of manufacture
If a bypass transistor with gate leakage is used, then the solution is cost-effective, but the application input range becomes limited
Solution Approach 1:
The charge pump performs preliminary charging of the capacitor to establish a voltage head before the bypass transistor operates. This preliminary action enables the circuit to handle a wider range of input voltages by ensuring sufficient charge is available to overcome gate leakage effects across different operating conditions, thus expanding the application input range while maintaining cost-effectiveness
Solution Approach 2:
The system implements feedback through the voltage sensing node that monitors the capacitor voltage. This feedback mechanism allows the control logic to adjust the charge pump operation and switch timing based on actual voltage conditions, enabling the circuit to adapt to various input voltage ranges and maintain stable operation across different applications
3Use of energy by moving object
If the pull-up resistor value is reduced to lower power consumption, then power consumption decreases, but the voltage drop on the pull-up resistor increases affecting the gate pull-up capability
Solution Approach 1:
The charge pump performs preliminary charging of the capacitor to build up voltage before the bypass transistor needs to switch. This preliminary action compensates for the voltage drop that would occur across a low-value pull-up resistor, maintaining sufficient gate pull-up capability while allowing the use of lower resistance values to reduce continuous power consumption
Solution Approach 2:
The capacitor acts as an intermediary energy storage element between the charge pump and the bypass transistor gate. It absorbs the charging current from the charge pump and provides a voltage boost to the gate, mediating the trade-off between pull-up resistor value, power consumption, and gate drive capability. This intermediary allows decoupling of the continuous power consumption from the instantaneous gate drive requirement
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 effectively addresses the limitations of conventional high-voltage startup regulators by reducing power consumption, expanding the application input range, and providing a cost-effective alternative to dedicated HV-MOS components.
Implementation Method 1
A charge pump is coupled to the current flow-path of the first electronic switch and configured to be activated with the second electronic switch switched to the conductive state to pump electric charge from the current flow-path of the first electronic switch to the control node of the first electronic switch
Implementation Method 2
A comparator is coupled to the voltage-sensing node and a threshold. The comparator is configured to compare a voltage at the voltage-sensing node with the threshold and generate the switch-on signal in response to the voltage at the voltage-sensing node reaching the threshold
Implementation Method 3
A voltage-sensing node is configured to be coupled to the high-voltage node via a pull-up resistor
Data Source
AI summary
A circuit includes an electronic switch configured to be coupled intermediate a high-voltage node and low-voltage circuitry and configured to couple the low-voltage circuitry to the high-voltage node. A voltage-sensing node is configured to be coupled to the high-voltage node via a pull-up resistor. A further electronic switch can be switched to a conductive state to couple the voltage-sensing node and the control node of the electronic switch. A comparator compares a threshold with a voltage at the voltage-sensing node and causes the further electronic switch to switch on in response to the voltage at said voltage-sensing node reaching said threshold. A charge pump coupled to the current flow-path of the electronic switch is activated to the conductive state to pump electric charge from the current flow-path of the electronic switch to the control node of the electronic switch via the further electronic switch switched to the conductive state.