User Selectable Pin for Voltage Regulator Capacitor Connection
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Solution Overview
Problem
Integrated circuit devices with internal voltage regulators face disruptions during start-up or power interruptions due to uncontrolled connections with external filter/stabilization capacitors, and there is a need for flexible pin selection, especially in low pin-count devices.
Innovation Solution
An integrated circuit device with user-selectable external connections allows for controlled coupling of the internal voltage regulator to an external capacitor, using pin selection based on stored allocation information and voltage equalization through high and low impedance paths to prevent voltage sag or spike.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal voltage regulator is connected to an uncharged or overcharged external filter capacitor during startup or power interruption, then the external capacitor can be charged or discharged, but the output of the internal regulator will droop or spike and proper operation is disrupted
Solution Approach 1:
The patent implements a startup sequence where the internal voltage regulator is first enabled to begin regulating voltage before the external filter capacitor is connected to its output. This preliminary action allows the regulator to establish stable operation and voltage levels before the capacitor is charged or discharged, preventing output droop or spike that would occur if the capacitor were connected first. The controller monitors startup conditions and sequences the enabling of the regulator and connection of the capacitor accordingly.
2Adaptability or versatility
If a specific external connection (pin) is dedicated for external regulator filter/stabilization capacitor connection, then the connection is fixed and simple, but flexibility in pin selection is lost which is especially disadvantageous for low pin-count integrated circuit devices
Solution Approach 1:
The patent implements dynamic pin allocation where the assignment of external connections (pins) to the internal voltage regulator is not fixed but can be changed based on operating conditions. The controller determines pin allocation information and can reconfigure which pins are assigned to the voltage regulator during different operational modes or startup scenarios. This dynamic reconfiguration capability provides flexibility for low pin-count devices to optimize pin usage while maintaining proper voltage regulator operation.
Solution Approach 2:
The patent enables external connections (pins) to serve multiple functions depending on the operational mode and pin allocation configuration. The same physical pin can be assigned to different functions including connecting to the internal voltage regulator, connecting to external circuitry, or being used for other purposes based on the pin allocation information stored in nonvolatile memory and the current operating conditions. This multi-functionality increases adaptability without requiring additional dedicated pins.
3Ease of operation
If pin selection for external capacitor connection is determined using low voltage logic that requires voltage from the internal voltage regulator, then pin selection can be made intelligently, but connecting the regulator output to an uncharged or differently charged capacitor causes voltage to sag or spike
Solution Approach 1:
The patent sequences operations so that the internal voltage regulator is enabled and begins regulating voltage before the pin selection logic determines and configures the external capacitor connection. This preliminary voltage establishment ensures that when the capacitor is subsequently connected to the regulator output, the voltage is already stable and the capacitor charges or discharges without causing significant sag or spike. The controller coordinates the timing of regulator enabling, pin selection, and capacitor connection to maintain voltage stability throughout the startup process.
Data Source
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AI summary
An integrated circuit device provides a choice of external pins (connections) that may be user selectable for coupling an external filter/stabilization capacitor to an internal voltage regulator. However, connecting the output of a internal voltage regulator to an uncharged external filter/stabilization capacitor (or to a capacitor charged to a different voltage level than the internal regulation voltage) through a low impedance path can cause the regulator output voltage to sag/spike if the internal voltage regulator tries to charge/discharge the capacitor up/down to equilibrium with the regulator output voltage. To minimize this potential sag/spike, the voltage on the external filter/stabilization capacitor may be adjusted in a controlled manner to substantially the same voltage as the voltage on the output of the internal voltage regulator, and then the internal voltage regulator is operationally coupled through a low impedance to the external regulator filter/stabilization capacitor.