Motor Drive Circuit Merging Saturation and Constant Voltage Control
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Solution Overview
Problem
Conventional motor drive systems require large circuit sizes due to independent circuits for different drive systems, and they have low control responsiveness, making them unsuitable for high-frequency switching operations like PWM control.
Innovation Solution
A motor drive circuit with a compact design that includes a first and second drive transistor, a first control unit for switching signals, and a second control unit with on-off, constant voltage, and constant current control sections, allowing switching between saturation, constant voltage, and constant current drive modes without increasing circuit size, and enabling high control responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent circuits are provided for different drive systems (saturation drive, constant voltage drive, constant current drive), then each drive system can be implemented with dedicated control, but the circuit size becomes large
Solution Approach 1:
The patent merges multiple independent drive circuits (saturation drive, constant voltage drive, constant current drive) into a single integrated motor drive circuit. The control unit selectively activates different drive modes by controlling the same output transistors, eliminating the need for separate dedicated circuits for each drive system while maintaining all required functionality.
Solution Approach 2:
The motor drive circuit is designed with multi-functionality, where a single circuit can operate in multiple drive modes (saturation drive, constant voltage drive, constant current drive) depending on the control signals received. The same output transistors and power supply circuit serve all drive modes, making the circuit universal rather than requiring separate dedicated circuits.
2Ease of manufacture
If conventional motor drive circuits are used, then circuit implementation is straightforward, but control responsiveness is low making them unsuitable for high-frequency switching operations
Solution Approach 1:
The control unit dynamically switches between different drive modes and rapidly adjusts transistor switching states in response to control inputs. This dynamic control capability enables high-frequency switching operations and fast response times while maintaining circuit implementation simplicity through a unified control architecture.
Solution Approach 2:
The circuit enables rapid parameter changes by selectively modifying the operating state of transistors and switching between different drive modes (saturation, constant voltage, constant current) through control signals. This allows fast response to changing load conditions and high-frequency PWM control while keeping the circuit structure simple and easy to manufacture.
Data Source
AI summary
Two systems consisting of an on-off control section corresponding to the saturation drive system and a constant voltage control section corresponding to the constant voltage drive system are provided as a circuit for controlling the conduction state of a transistor QP11 provided at the output section. The constant voltage unit comprises an operational amplifier A1, which monitors the output voltage Vout and feedback-controls the gate voltage of QP11. On the other hand, the on-off control section delivers a control signal for turning on and off QP11 corresponding to an input signal input to IN-U through inverters 40 and 42. Switches 46 and 48 for selectively applying the output from the control unit of either one of these two systems are provided to select the switch to be turned on based on a mode signal input to SW. This configuration enables the realization of different drive systems and restricts increase in circuit size while commonly using the output unit configured with comparatively large transistors. In addition, since the saturation drive system can be realized without depending on feedback control, high control responsiveness is secured to appropriately perform operation at high frequencies such as switching operations by PWM control.