Cascoded Power Stage With Voltage Clamps for 200V Buck Conversion

Solution Overview

Problem

Existing buck voltage converters face challenges in handling input voltages above 100V, as standard semiconductor processes either result in high on-resistance or require larger die sizes and higher costs when using high voltage processes, and cascoded transistor configurations have limitations in managing higher input voltages effectively.

Innovation Solution

A power driver circuit and voltage regulator circuit design using cascoded transistors with voltage clamp circuits to manage high input voltages, ensuring each transistor's maximum voltage ratings are not exceeded, and employing a combination of clamp circuits to protect against overvoltage conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a high voltage semiconductor process is used to handle input voltages of 200V or higher, then the device can operate at higher voltages, but the on-resistance becomes significantly higher than in lower voltage processes

Engineering Contradiction:

Improveinput voltage rangeVSAvoidon-resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The power switch is divided into two separate transistors connected in series: a first transistor handling the high voltage portion and a second transistor handling the low voltage portion. This segmentation allows each transistor to be optimized for its specific voltage range, with the first transistor designed for high voltage operation and the second transistor providing low on-resistance for efficient current conduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the circuit are given different characteristics: the first transistor is designed with high voltage tolerance but higher on-resistance, while the second transistor is designed with low on-resistance for efficient power conduction. This local optimization allows the overall system to achieve both high voltage capability and low total on-resistance.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a high voltage semiconductor process is used to handle input voltages of 200V or higher, then the device can operate at higher voltages, but the die size becomes significantly larger than in lower voltage processes

Engineering Contradiction:

Improveinput voltage rangeVSAvoiddie size

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The power switch is divided into two separate transistors connected in series: a first transistor handling the high voltage portion and a second transistor handling the low voltage portion. This segmentation allows each transistor to be optimized for its specific voltage range, with the first transistor designed for high voltage operation and the second transistor providing low on-resistance for efficient current conduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the voltage rating parameter of the transistors used in the circuit. By selecting a first transistor with a voltage rating matching the input voltage (200V or higher) and a second transistor with a lower voltage rating, the circuit achieves high voltage operation without requiring all components to be designed for the highest voltage, thereby reducing overall die size.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If cascoded transistor configurations are used to manage high input voltages, then voltage distribution is improved, but the device complexity increases

Engineering Contradiction:

Improvevoltage management capabilityVSAvoidcircuit configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The power switch is divided into two separate transistors connected in series: a first transistor handling the high voltage portion and a second transistor handling the low voltage portion. This segmentation allows each transistor to be optimized for its specific voltage range, with the first transistor designed for high voltage operation and the second transistor providing low on-resistance for efficient current conduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A voltage distribution circuit is introduced as an intermediary between the input voltage source and the transistors. This circuit automatically distributes the input voltage between the first and second transistors, ensuring that each transistor operates within its voltage rating without requiring complex external control circuitry.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250350279A1High Voltage Converter Power Stage

Publication Date: 2025.11.13 TEXAS INSTRUMENTS INC

AI summary

Described embodiments include a power driver circuit having a first transistor coupled between an input voltage terminal and an intermediate terminal, and having a first control terminal. A second transistor is coupled between the intermediate terminal and a switching terminal, and has a second control terminal coupled to an output of a gate drive circuit. A first diode has a first anode coupled to the input voltage terminal, and a first cathode coupled to the first control terminal through a resistor. A first voltage clamp circuit is coupled between the first control terminal and the intermediate terminal. A second voltage clamp circuit is coupled between the first control terminal and the switching terminal. A second diode is coupled between the first control terminal and a voltage supply terminal.