Voltage-Dependent Oscillator Delay for Stable Pump Startup
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Solution Overview
Problem
The development of internal voltages in semiconductor devices is slow and unpredictable, leading to potential circuit failures during startup, as the rate of internal voltage development depends on the external voltage ramp-up and can differ after reaching the operating level.
Innovation Solution
The implementation of a voltage pump system with an oscillator and delay circuits that regulate the pump input based on comparator signals, adjusting the frequency of the output signal to control the development of internal voltages, ensuring they reach the required levels efficiently and consistently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the external voltage is ramped up quickly to reach operating level, then the startup time is reduced, but the internal voltage development becomes unpredictable and may cause circuit failures
Solution Approach 1:
The voltage pump operates in periodic cycles, alternately connecting pump capacitors to charge nodes and discharge nodes. This periodic charging and discharging action creates a controlled ramp-up of internal voltages, ensuring predictable development while maintaining fast startup. The oscillator generates periodic pump input signals that drive this cyclic operation.
Solution Approach 2:
The comparator continuously compares the developed internal voltage against a reference voltage and generates feedback signals to control the voltage pump operation. This feedback mechanism ensures the internal voltage reaches the required level reliably while preventing over-voltage conditions, thus maintaining circuit reliability during startup.
2Speed
If the voltage pump operates at high frequency to accelerate internal voltage development, then the startup speed is improved, but the power consumption increases
Solution Approach 1:
The voltage pump frequency is dynamically adjusted based on the development stage of internal voltages. During initial startup when fast voltage development is needed, the oscillator operates at higher frequency. Once internal voltages approach the reference level, the frequency automatically decreases, reducing power consumption while maintaining reliable voltage development.
Solution Approach 2:
The system changes the operating frequency parameter of the voltage pump based on the internal voltage development progress. The comparator detects voltage levels and controls the oscillator frequency accordingly, transitioning from high-frequency operation during startup to lower-frequency operation during steady-state, thus optimizing the balance between speed and power consumption.
Data Source
AI summary
Apparatus and methods are described for voltage dependent delay. An example apparatus includes an oscillator including a delay circuit that is configured to provide an oscillating output signal has a delay based on a delay of the delay circuit. The delay of the delay circuit is based on a voltage it receives. For example, the delay of the delay circuit increases for an increasing received voltage and decreases for a decreasing received voltage. As a result, the oscillating output signal provided by the oscillator is based on the received voltage. For example, a frequency of the oscillating output signal decreases for increasing received voltage and increases for decreasing received voltage. Described in another way, the frequency of the oscillating output signal is relatively low for relatively high received voltage and relatively high for relatively low received voltage.