SMPS Controller Pin Multiplexing for Adjustable Blanking Time
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Solution Overview
Problem
Switched mode power supply (SMPS) controllers have limited pin count, making it difficult to implement adjustable functions like blanking time, external shutdown, and internal frequency selection efficiently, especially in digital designs where the blanking time is not easily adjustable.
Innovation Solution
An integrated circuit with a controller that receives a feedback signal and uses an external capacitor to set an adjustable blanking time, allowing multiple functions such as blanking time, external shutdown, and internal frequency selection to be implemented on a single pin, enabling adjustable operation while minimizing pin count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a digital design is used for blanking time function, then chip space and current consumption are reduced, but blanking time becomes not easily adjustable
Solution Approach 1:
The patent implements a digital counter that can be dynamically reconfigured to change the blanking time period. The counter is enabled or disabled based on an external control signal, allowing the blanking time to be adjusted dynamically without changing the physical circuit structure. This resolves the contradiction by maintaining the low current consumption of digital design while adding adjustability through dynamic control.
Solution Approach 2:
The patent changes the operational parameters of the digital counter by controlling its enable/disable state through an external control signal. By changing the enable parameter of the counter based on external conditions, the blanking time can be adjusted without modifying the digital circuit structure itself. This allows the system to maintain digital efficiency while gaining adjustability through parameter control.
2Adaptability or versatility
If multiple functions are implemented on separate pins, then each function can be independently configured, but pin count increases
Solution Approach 1:
The patent merges multiple functions (feedback signal reception, blanking time control, and external shutdown) into a single pin. The feedback pin can selectively receive different signals based on the state of an external control signal, allowing multiple functions to be combined in one physical connection point. This reduces pin count while maintaining the ability to independently configure each function through control signals.
Solution Approach 2:
The patent makes the feedback pin universal by enabling it to serve multiple purposes: receiving feedback signals for voltage regulation, controlling the blanking time period, and providing external shutdown capability. The pin's function is determined dynamically by external control signals, allowing one pin to perform the work of multiple dedicated pins while maintaining independent configuration of each function.
3Ease of operation
If an analog design is used for blanking time function, then blanking time is easily adjustable using external capacitor, but chip space and current consumption increase
Solution Approach 1:
The patent replaces the analog capacitor-based timing mechanism with a digital counter system. Instead of using an external capacitor to set the blanking time period through analog charging/discharging, the system uses a digital counter controlled by clock cycles. This substitution eliminates the need for large external capacitors and reduces current consumption while maintaining adjustability through digital control signals.
Solution Approach 2:
The patent changes the method of parameter control from analog (capacitor value) to digital (control signals enabling/disabling the counter). By changing how the blanking time parameter is controlled - from physical capacitor sizing to digital enable/disable signaling - the system achieves similar adjustability with much lower current consumption and reduced external component requirements.
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
This solution allows for flexible and efficient implementation of multiple functions on a single pin, enhancing the operational flexibility and adjustability of SMPS controllers without increasing pin count, particularly improving the digital design's ability to set adjustable blanking times.
Implementation Method 1
A blanking time circuit includes a capacitor charged by a current source to a threshold voltage
Data Source
AI summary
An integrated circuit includes a controller configured to regulate an output of a power supply based on a first signal. The integrated circuit includes an input configured to receive the first signal and to be coupled to an external capacitor that sets an adjustable blanking time for the power supply.