Switching Regulator Control Circuit With Single Pin Frequency Setting
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Solution Overview
Problem
Conventional control circuits for switching regulators require multiple pins for frequency setting, which increases chip packaging area and reduces selection flexibility.
Innovation Solution
A control circuit with a control pin, resistor detecting circuit, current generating module, oscillating circuit, and mode-switching circuit that allows for two clock frequency setting modes: resistor-controlled and signal-controlled, using a single control pin to generate clock signals based on external resistor values or synchronous signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple pins are used for frequency setting and synchronous signal input, then selection flexibility in setting clock signal frequency is improved, but chip packaging area increases
Solution Approach 1:
The patent combines the frequency setting function and synchronous signal input function into a single control pin. The control pin can accept either an external resistor for frequency setting or an external synchronous signal, merging two previously separate functions into one pin, thereby reducing chip packaging area while maintaining frequency setting flexibility
Solution Approach 2:
The control pin is designed with multi-functionality, serving both as a frequency setting input (when connected to external resistor) and as a synchronous signal input (when connected to external synchronous signal source). This universal pin replaces what would traditionally require two separate pins, reducing the overall pin count and chip area
2Area of stationary object
If a single control pin is used for both frequency setting and synchronous signal input, then chip packaging area is reduced, but circuit complexity increases
Solution Approach 1:
The control circuit automatically detects whether an external resistor or synchronous signal is connected to the control pin and self-adjusts its operating mode accordingly. The circuit performs self-diagnosis and mode selection without requiring external control signals, reducing the need for additional control pins and simplifying the overall system complexity despite the multi-functional pin design
Data Source
AI summary
A control circuit of a switching regulator includes a control pin for coupling with an external resistor; a resistor detecting circuit for detecting a resistance of the external resistor; a current generating module for generating a corresponding control current according to a detection result of the resistor detecting circuit; an oscillating circuit for generating a clock signal; and a mode-switching circuit. When the mode-switching circuit configures the oscillating circuit to operate in a resistor-controlled mode, the oscillating circuit generates the clock signal according to the control current so that the clock signal has a frequency corresponding to the resistance of the external resistor. When the mode-switching circuit configures the oscillating circuit to operate in a signal-controlled mode, the oscillating circuit generates the clock signal according to an external synchronous signal coupled with the control pin so that the clock signal is synchronized with the external synchronous signal.