Low Voltage Bandgap Reference Circuit Startup Mechanism

The patent modifies the operating parameters of the bandgap reference circuit by introducing a startup circuit that temporarily alters the circuit state during initialization. This startup circuit provides a temporary bias current that shifts the operating point from an unstable region to a stable region, enabling the circuit to achieve a single stable operating point that can reliably operate at low supply voltages below 1.25V while maintaining temperature stability through the original positive and negative temperature coefficient cancellation mechanism

The patent implements a startup circuit that performs preliminary action before the main bandgap reference circuit operation. This startup circuit is activated first to establish the correct operating point and bias conditions, preventing startup failures. The startup circuit includes a startup transistor and associated components that provide temporary biasing until the main circuit stabilizes, ensuring reliable operation at low voltage without increasing steady-state power consumption

The patent extracts or removes the problematic multiple stable operating points from the circuit by introducing a startup mechanism that forces the circuit into a single desired operating state. The startup circuit effectively eliminates the unwanted alternative operating points by providing a dominant initialization path, ensuring that the circuit converges to the correct single stable operating point regardless of initial conditions, thereby improving startup reliability while maintaining the necessary operating flexibility