Active Pull-Up System for Motor Current Reduction
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Solution Overview
Problem
Existing cooling systems for electronic devices face challenges in efficiently managing motor current consumption during standby modes, which affects the overall performance and efficiency of cooling systems.
Innovation Solution
The active pull-up system (APS) is introduced, which includes a circuit with a pull-up resistor and a switching device to minimize current consumption during sleep mode and enhance communication speeds by adjusting resistance levels, utilizing a comparator and latch to manage the output node's voltage and slew rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a passive pull-up system is used, then the circuit is simple, but current consumption during standby mode is high
Solution Approach 1:
The patent applies dynamics by making the pull-up resistance variable rather than fixed. The circuit dynamically adjusts the resistance value based on the operational state: using a low resistance value (e.g., 50kΩ) during active mode for fast communication, and a high resistance value (e.g., 2MΩ) during standby mode to minimize current consumption. This is achieved through a state machine that controls switching devices to reconfigure the resistor network according to the desired operational state.
Solution Approach 2:
The patent segments the pull-up resistance function into multiple resistive paths that can be independently controlled. Instead of a single fixed resistor, the circuit uses multiple resistors (e.g., R1=50kΩ, R2=2MΩ, R3=500kΩ) arranged in a network controlled by switching devices (M1, M2, M3). This segmentation allows selective activation of different resistance values based on operational requirements, enabling both fast communication and low standby current.
2Speed
If resistance is reduced for fast communication, then communication speed increases, but current consumption increases
Solution Approach 1:
The circuit dynamically switches between low resistance (for fast communication) and high resistance (for low current consumption) based on the operational state. During active communication, the state machine activates switching devices to connect low-value resistors in parallel, providing fast pull-up. During standby, the switching devices reconfigure to connect only high-value resistors, minimizing current while maintaining the ability to quickly transition back to fast communication mode.
Solution Approach 2:
The state machine implements periodic monitoring and adjustment of the pull-up resistance based on communication activity detection. When communication is detected, the circuit transitions to low-resistance mode; when idle, it transitions to high-resistance mode. This periodic state adjustment ensures optimal performance characteristics are active only when needed.
Data Source
AI summary
An active pull-up system for use with a motor is described. The active pull-up system comprises: a first resistor coupled to an output node; a first switch and a second resistor coupled in parallel with the first resistor, wherein the first switch is in series with the second resistor; a latch coupled to the first switch for either keeping the first switch open or closing the first switch in response to receiving a closing signal; and a threshold comparator coupled between the output node and the latch, wherein the threshold comparator transmits the closing signal when the output node exceeds a threshold value, which actively pulls up the output node.