Load Switch with Programmable Filter Response for Noise Attenuation
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Solution Overview
Problem
Existing power systems in portable devices face inefficiencies due to noise introduction from DC/DC converters and the need for bulky passive filters, which increase cost and reduce battery life, as analog switches and low dropout regulators (LDOs) fail to provide effective multi-order wideband filtering.
Innovation Solution
A load switch with a pass element and control terminal that maintains high impedance and a defined response, incorporating a gain element and optimized drop reference circuit to regulate voltage drop and provide programmable filter responses, replacing the need for discrete filters and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive filter components are added to attenuate noise from DC/DC converters, then noise filtering is improved, but board space and system cost increase
Solution Approach 1:
The patent combines the filtering function with the load switch by integrating a control circuit that provides multi-order wideband filtering within the switch itself. This merges two previously separate functions (switching and filtering) into a single integrated component, eliminating the need for external passive filter components and thereby reducing board space while maintaining effective noise attenuation.
Solution Approach 2:
The load switch is designed to perform multiple functions simultaneously: power switching, voltage regulation, and multi-order wideband filtering. The control circuit within the switch provides filtering across multiple frequency bands, making the switch a universal component that replaces both the traditional switch and separate filter components, thus reducing overall system complexity and board space.
2Object-affected harmful factors
If passive filter components are added to attenuate noise from DC/DC converters, then noise filtering is improved, but system cost increases
Solution Approach 1:
By integrating the filtering function into the load switch, the patent reduces the total component count and eliminates the need for separate passive filter components. This consolidation reduces system cost by reducing parts procurement, assembly, and testing costs while maintaining effective multi-order wideband noise filtering capability.
3Object-affected harmful factors
If LDO is used for filtering, then noise attenuation is provided, but voltage drop increases and efficiency decreases
Solution Approach 1:
The patent employs a dynamic control circuit that actively adjusts the switching element's operation to provide filtering, replacing the static voltage dropping mechanism of traditional LDOs. This dynamic approach maintains lower voltage drop and higher efficiency by using controlled switching rather than continuous linear regulation, while still achieving effective noise attenuation through the multi-order wideband filtering provided by the control circuit.
Solution Approach 2:
The patent replaces the linear voltage regulation mechanism of LDOs with a switching-based control system. This substitution uses pulsed width modulation or similar switching techniques controlled by a feedback circuit to achieve filtering, thereby reducing the continuous power dissipation and voltage drop characteristic of LDOs while maintaining noise attenuation performance.
4Object-affected harmful factors
If multi-order wideband filter response is provided using traditional solutions, then filtering performance is improved, but component proliferation occurs
Solution Approach 1:
The patent integrates multiple filtering functions into a single control circuit within the load switch. The control circuit is designed to provide multi-order wideband filtering by combining multiple filtering mechanisms or stages within one integrated block, thereby achieving complex filtering performance without requiring multiple separate filter components and reducing overall device complexity.
Solution Approach 2:
The load switch is designed as a universal component that simultaneously provides switching, voltage regulation, and multi-order wideband filtering functions. The control circuit within the switch is capable of providing filtering across multiple frequency bands and orders, making the switch a multi-functional device that replaces both the switch and separate filter components, thus reducing component proliferation while maintaining superior filtering performance.
Data Source
AI summary
A semiconductor device, circuit, and AC and DC load switch for maintaining a small input-output differential voltage and providing a defined response. The load switch can include a pass element coupled to an input terminal and an output terminal. The pass element can include a control terminal, with the control terminal controlling a response of the pass element. The load switch can include a first loop coupled to the control terminal configured to control a voltage drop between the input terminal and the output terminal while maintaining high impedance with the pass element. The load switch can include a second loop coupled to the control terminal configured to provide a defined filter response from the input terminal. The defined response can be a low pass response, high pass response, or a band pass response. The passband and/or stopband of the response can be programmed.