Boost Circuit Mode Transition for Input Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional synchronous rectification boosting PFM-controlled power supply devices face issues with high power consumption and voltage ripple when the input voltage is higher than the target voltage, due to parasitic diodes causing the output voltage to be stuck above the target voltage, leading to malfunctioning and inefficiency.
Innovation Solution
A boost circuit with a controller that transitions to a non-conducting state between the input and output terminals when the input voltage exceeds the target voltage, using a boost converter with inductor, capacitor, and switching elements to manage modes of operation and forcibly switch to a mode where the first switching element is off and the second is on, reducing power loss and voltage ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If synchronous rectification boosting PFM-controlled type power supply device is used, then power consumption is reduced at light loads, but output voltage cannot be lowered below target voltage when input voltage is higher than target voltage plus diode voltage, causing high power consumption
Solution Approach 1:
The patent applies dynamics by making the power supply device switch between two different operating modes: PFM-controlled synchronous rectification boosting mode for normal operation, and forced CM mode when input voltage exceeds target voltage plus diode voltage. This dynamic switching allows the system to adapt to different input voltage conditions and maintain proper output voltage control while minimizing power consumption in both scenarios
Solution Approach 2:
The patent changes the operating parameter (control mode) based on the input voltage level. When input voltage is higher than target voltage plus diode voltage, the controller forces transition to CM mode where both switches are turned off simultaneously, changing the circuit's electrical parameters to bypass the parasitic diode conduction issue and enable proper output voltage regulation
2Reliability
If parasitic diode is always on when input voltage is higher than target voltage plus diode voltage, then output voltage is stuck above target voltage, but power loss increases due to continuous diode conduction
Solution Approach 1:
The patent extracts the parasitic diode from the current path by forcing both switches SWL and SWH to be turned off simultaneously in CM mode. This extraction removes the parasitic diode conduction path when input voltage is higher than target voltage plus diode voltage, eliminating the unwanted voltage drop and power loss while maintaining output voltage stability through capacitive discharge
3Power
If boost converter operates in conventional mode, then voltage boosting is achieved, but voltage ripple increases when input voltage is close to target voltage plus diode voltage
Solution Approach 1:
The patent dynamically switches to CM mode when input voltage approaches target voltage plus diode voltage threshold. This dynamic mode change prevents the voltage ripple issue by avoiding the problematic operating region where conventional boost mode会产生 large voltage ripple, while maintaining the ability to provide voltage boosting when needed through PFM-controlled synchronous rectification boosting mode
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
This solution reduces power consumption and prevents malfunctioning by maintaining a stable output voltage close to the input voltage, significantly reducing voltage ripple and power loss, thereby enhancing the efficiency of the power supply device.
Implementation Method 1
Current flows from input side terminal Tin through inductor L and between D (drain)—S (source) of switch SWL to ground. Energy is stored in inductor L by this.
Implementation Method 2
switch SWH is on, and switch SWL is off in accordance with control signals HCNT and LCNT. Current flows to the output side according to the energy stored in inductor L, and output voltage VBoost is boosted by this.
Data Source
AI summary
The objective of this invention is to provide a boost circuit that reduces power consumption and prevents malfunctioning when the input voltage becomes greater than a target voltage for the output voltage. Control circuit module 5 sets both control signals HCNT2 and LCNT2 to low level “L” when the conditions “output voltage VBoost is higher than voltage OVREF” and “voltage (VIN+VOFFSET) is higher than output voltage VBoost” are satisfied. With this, in boost circuit module 7, switch SWH will be off and switch SWL will be on to forcibly switch to mode B. In mode B, because switch SWH is on, output voltage VBoost will be near input voltage VIN, and the power consumption can be reduced.