Power Management IC Supervisory Circuit Start-Up Integration
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Solution Overview
Problem
Power management integrated circuits face high power consumption due to continuous current flow through resistors during normal operation, which increases silicon surface area and energy usage.
Innovation Solution
The integration of the start-up unit and switch within the supervisory circuit, eliminating the need for a separate start-up resistor in the reference signal generator, allowing the resistor circuit to function only during the start-up phase and normal operation, reducing power consumption and silicon area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate start-up resistor is used in the reference signal generator, then reliable start-up current generation is achieved, but power consumption increases and silicon surface area increases
Solution Approach 1:
The patent combines the start-up circuit functionality with the supervisory circuit by integrating the start-up unit and switch into the supervisory circuit structure. The resistor circuit that was previously separate is now shared between the supervisory circuit and start-up functions. This merging eliminates the need for a separate start-up resistor, reducing both power consumption and silicon area while maintaining reliable start-up operation through the same resistor circuit being used for both voltage monitoring and start-up current generation.
2Reliability
If a separate start-up resistor is used in the reference signal generator, then reliable start-up current generation is achieved, but silicon surface area increases
Solution Approach 1:
The patent merges the start-up resistor function with the supervisory circuit resistor circuit, eliminating the need for a separate dedicated start-up resistor. The same resistor circuit serves dual purposes: monitoring supply voltage levels for supervisory functions and providing start-up current when needed. This integration significantly reduces the silicon surface area required while maintaining all necessary functionalities.
Solution Approach 2:
The resistor circuit in the supervisory circuit is designed to serve multiple functions: it acts as a voltage divider for supply voltage monitoring, provides start-up current when the start-up unit activates the switch, and enables both supervisory and start-up operations using a single physical component structure. This multi-functionality reduces the overall component count and silicon area.
3Measurement precision
If continuous current flows through resistors during normal operation, then voltage monitoring is maintained, but power consumption increases
Solution Approach 1:
The patent implements dynamic control of the resistor circuit current through the start-up switch. During normal operation, the switch remains closed, allowing the resistor circuit to function for voltage monitoring with minimal current draw. When start-up is needed, the start-up unit opens the switch to enable start-up current flow. This dynamic switching optimizes power consumption by activating current flow only when necessary for start-up or monitoring, rather than maintaining continuous high current.
Solution Approach 2:
The start-up circuit operates periodically rather than continuously - the start-up unit monitors conditions and activates the switch only when start-up is required or when supervisory monitoring needs to occur. This periodic activation of current flow through the resistor circuit reduces average power consumption while maintaining the ability to perform voltage monitoring and start-up functions when needed.
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
Significantly reduces power consumption and maintains efficient start-up and normal operation phases with a smaller integrated circuit footprint.
Implementation Method 1
The generation of the start-up current is triggered directly by a detection that the supply voltage Vbat is at a high level, i.e., that the input voltage detected by the start-up unit is above the voltage threshold which is generated by the start-up unit itself
Implementation Method 2
The start-up unit 21, after having closed the switch 17, is arranged to maintain a supply voltage on the control gate of the switch as long as the bias current Ibias is within the given normal range
Implementation Method 3
The start-up unit is also arranged for detecting whether the reference current generator 11 has started to operate correctly, in order to terminate the start-up phase, by detecting whether a bias current Ibias, provided by this reference current generator
Data Source
Figure 1
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Figure 3
AI summary
The present invention concerns a power management integrated circuit (1) comprising a reference signal generator (3A), a start-up unit (21) and a supervisory circuit (7A). The supervisory circuit comprises: - an electrical resistance circuit (25) connected between a first end node and a second end node; - a power supply input (19) for receiving a supply voltage, this power supply input being connected to the first end node; - a low reference potential node (GND); - a comparator (31) for comparing a reference voltage value (Vref) at a first input and a divided voltage value (VLev1) at a second input connected to an internal electrical node of the electrical resistance circuit, the comparator (31) being configured to output a monitoring signal. The supervisory circuit further comprises a switch (17) between the second end node and the low reference potential node, this switch being controlled by the start-up unit (21) so that the switch is selectively closed and opened based on a detected operational state of the reference signal generator indicating a normal functioning phase of the power management circuit.