DC/DC Converter Driver Voltage Isolation for Switch Stability
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Solution Overview
Problem
Existing DC/DC converters face challenges in efficiently managing power for multiple power switches, leading to potential damage and instability in the system.
Innovation Solution
A DC/DC converter design featuring a serial string of power switches with capacitors and inductors, along with dedicated drivers generating switching control signals, where the voltage for drivers has no correlation with the input terminal voltage, ensuring stable operation and reduced switch damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If drivers are powered from the input terminal voltage in a DC/DC converter with multiple series power switches, then the circuit structure is simple, but the power switches may be damaged due to voltage fluctuations and lack of stable power supply
Solution Approach 1:
The power supply system is segmented into independent modules: each driver receives power from dedicated voltage sources (VDD and VSS) rather than sharing the input terminal voltage. This segmentation isolates the control circuitry from input voltage fluctuations, ensuring stable operation of power switches even when input voltage varies.
Solution Approach 2:
Dedicated voltage sources (VDD and VSS) act as intermediary elements between the input power and the drivers. These intermediaries buffer and stabilize the voltage supplied to drivers, preventing direct transmission of input voltage fluctuations to the power switch control circuits.
2Strength
If multiple power switches are connected in series to handle higher voltage, then the voltage handling capability increases, but the power management complexity and risk of switch damage increase
Solution Approach 1:
Each power switch in the series string is provided with locally optimized power supply conditions through dedicated VDD and VSS connections. This local quality approach ensures that each switch operates with stable, appropriate voltage levels independent of the overall string voltage, simplifying individual switch management while maintaining high voltage handling capability.
Solution Approach 2:
The dedicated voltage source configuration serves multiple functions simultaneously: it provides stable power to all drivers, isolates them from input fluctuations, and enables reliable operation of series-connected switches. This universal approach simplifies the overall power management despite the increased voltage handling requirements.
3Ease of manufacture
If the driver voltage is correlated with the input terminal voltage, then the circuit design is straightforward, but the drivers may not operate stably when input voltage fluctuates
Solution Approach 1:
The voltage sources VDD and VSS are configured to provide predetermined, stable voltage levels to the drivers before the power switching operation begins. This preliminary establishment of stable voltage conditions ensures that drivers operate reliably regardless of subsequent input voltage fluctuations during converter operation.
Data Source
AI summary
In a DC/DC converter, a driving method thereof, and a power supply using the same, the DC/DC converter includes a plurality of power switches connected as a serial string between an input terminal and a ground terminal, a first capacitor connected to at least two power switches of the serial string in parallel, an inductor connected between an intermediate node of the serial string and an output terminal, a second capacitor connected between the output terminal and the ground terminal, and a plurality of drivers configured to generate a switching control signal for each of the plurality of power switches. A voltage having no correlation with a voltage of the input terminal is supplied to a power terminal of each of the plurality of drivers.