Bandgap Reference Startup Circuit for Low-Spike Fast Stabilization
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Solution Overview
Problem
Current starting circuits for bandgap reference voltage generation circuits suffer from drawbacks such as significant current spikes, long stabilization times, and potential oscillations during startup, which hinder efficient operation.
Innovation Solution
A starting circuit for bandgap reference voltage generation circuits is designed with a current mirror configuration that includes specific transistor arrangements and resistor connections, allowing for a controlled startup process that limits current overloads and reduces stabilization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional starting circuit is used to initiate bandgap reference voltage generation, then the circuit can be activated, but significant current spikes occur during startup
Solution Approach 1:
The starting circuit activates transistor M4 in advance to pre-charge the gate of transistor M2 before the main bandgap circuit is fully activated. This preliminary action ensures that when the bandgap circuit starts, the current increases gradually rather than spiking suddenly, thus maintaining reliable startup while limiting current surge.
2Reliability
If a conventional starting circuit is used to initiate bandgap reference voltage generation, then the circuit can be activated, but long stabilization times occur
Solution Approach 1:
Transistor M4 is activated beforehand to pre-charge the gate capacitance of transistor M2. This preliminary charging action reduces the time required for the bandgap reference voltage to stabilize after startup, achieving fast stabilization while maintaining reliable circuit activation.
3Reliability
If a conventional starting circuit is used to initiate bandgap reference voltage generation, then the circuit can be activated, but oscillations occur during startup
Solution Approach 1:
The starting circuit with transistor M4 performs preliminary charging of the gate of transistor M2 before the main circuit operates. This gradual voltage buildup prevents sudden voltage changes that could trigger oscillations, ensuring both reliable startup and voltage stability during the startup phase.
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 proposed solution effectively minimizes current spikes and stabilizes the output voltage within 5 µs, ensuring stable operation without oscillations.
Implementation Method 1
a fourth MOS transistor between a supply voltage application terminal and a control terminal of the second transistor, the fourth MOS transistor being mounted in current mirror on the first MOS transistor
Implementation Method 2
a second transistor and a third current mirror transistor whose control terminals are connected by a first resistor
Implementation Method 3
bandgap reference voltage generation circuit configured to generate a reference voltage that does not globally vary with temperature
Data Source
Figure 1
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Figure 4
AI summary
The present description relates to a starting circuit (420) of a bandgap reference voltage generation circuit (110) whose current mirror comprises a first MOS transistor (MP2), comprising: a second transistor (MNR) and a third transistor (MNP) in current mirror whose control terminals are connected by a first resistor (ROFF); and a fourth MOS transistor (MP1) between a supply voltage application terminal (Vcc) and a control terminal (NB) of the second transistor (MNR), the fourth MOS transistor (MP1) being mounted in current mirror on the first MOS transistor (MP2).