Hysteretic Control Conversion Circuit Voltage Precision
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Solution Overview
Problem
Existing hysteretic BUCK converters experience instability in output voltage, leading to errors between actual and desired output voltages due to parasitic series resistors and circuit structure, resulting in precision issues.
Innovation Solution
A hysteretic control conversion circuit with a PMOS and NMOS transistor configuration, a first voltage divider resistor string, a comparator, and a logic controller, along with a negative feedback module that performs negative feedback control to clamp the output voltage to a preset reference voltage, ensuring stability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hysteretic control is used in BUCK converter, then response speed is improved, but output voltage precision deteriorates due to parasitic resistors and circuit structure
Solution Approach 1:
The patent introduces a negative feedback module that samples the output voltage through a voltage divider and feeds it back to the comparator. This feedback mechanism allows the system to continuously monitor and correct the output voltage, compensating for errors caused by parasitic resistors and circuit structure, thereby maintaining high precision while preserving the fast response characteristics of hysteretic control
Solution Approach 2:
The patent replaces the traditional voltage sampling method with a current sampling approach using an operational amplifier. The op-amp converts the voltage feedback signal into a current signal that can be directly compared with the inductor current, eliminating the need for additional resistive voltage division and reducing the impact of parasitic resistors on precision
2Device complexity
If parasitic series resistor of inductor is not considered, then circuit complexity is reduced, but output voltage error increases
Solution Approach 1:
The negative feedback module continuously monitors the actual output voltage and compares it with the reference voltage, automatically adjusting the duty cycle to compensate for voltage drops across parasitic resistors. This allows the system to maintain high precision without requiring complex compensation circuits or detailed knowledge of parasitic parameter values
Solution Approach 2:
The system uses its own output voltage signal to generate the feedback correction, making the compensation mechanism self-regulating. The operational amplifier automatically adjusts the comparator input based on the actual output conditions, eliminating the need for external adjustment components or complex calibration procedures
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
The solution effectively eliminates output voltage errors and improves precision by maintaining a stable output voltage, enhancing the hysteretic BUCK's precision and transient response.
Implementation Method 1
when VF is lower than a reference voltage VREF of a comparator 4, the PMOS transistor 1 is turned on and the NMOS transistor 2 is turned off
Implementation Method 2
a negative feedback module connected between the voltage output terminal and the input terminal of the comparator, and configured to perform negative feedback control over an output voltage of the hysteretic control conversion circuit and clamp the output voltage to a preset reference voltage
Implementation Method 3
the PMOS transistor 1 is turned on and the NMOS transistor 2 is turned off, and the LX terminal of the inductor L is connected to an input voltage Vin
Data Source
AI summary
The invention discloses a hysteretic control conversion circuit. The circuit includes a PMOS transistor and an NMOS transistor that are connected in series between a voltage input terminal and a ground terminal, a first voltage divider resistor string connected in series between a voltage output terminal and the ground terminal, a comparator, and a logic controller, where an output terminal of the comparator is connected to an input terminal of the logic controller, and two output terminals of the logic controller are respectively connected to grid electrodes of the PMOS transistor and the NMOS transistor. The hysteretic control conversion circuit also includes: a negative feedback module connected between the voltage output terminal and the input terminal of the comparator, and configured to perform negative feedback control over an output voltage of the hysteretic control conversion circuit and clamp the output voltage to a preset reference voltage.