Power Converter Standby Control via Latched Coded Signals
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Solution Overview
Problem
Power converters consume excessive energy when in low-power standby mode due to continuous signaling from the secondary-side controller to inhibit the power switch operation, leading to inefficient operation during light-load and no-load conditions.
Innovation Solution
Implementing a start-up controller on the primary side that uses digitally coded commands via isolation circuits to latch the enabling and disabling of the power switch, allowing the secondary-side controller to stop sending continuous disable signals, thereby reducing power consumption by transitioning to a passive low-power sleep mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the secondary-side controller continuously sends disable signals to inhibit power switch operation during standby mode, then the power converter can maintain a low-power state, but excessive energy is consumed by the continuous signaling process
Solution Approach 1:
The patent replaces continuous disable signaling with periodic action by using a one-time coded disable signal that latches the power switch in an inhibited state. The secondary-side controller sends a coded disable signal through the isolation circuit, which is decoded by the start-up controller to set a latch bit, maintaining the inhibited state without requiring continuous signals. This periodic/latched action dramatically reduces energy consumption during standby mode while maintaining the low-power state.
2Loss of energy
If the secondary-side controller stops sending continuous disable signals to reduce power consumption, then energy loss is reduced, but the power switch may inadvertently activate
Solution Approach 1:
The patent implements self-service through a self-latching mechanism where the start-up controller automatically maintains the inhibited state once a coded disable signal is received. The decoded disable signal sets a latch bit in the start-up controller that automatically keeps the power switch inhibited without requiring external continuous control. This self-latching mechanism ensures reliable power switch inhibition while eliminating continuous signaling, achieving both energy reduction and reliability maintenance.
Solution Approach 2:
The patent uses feedback through coded signals transmitted from the secondary-side controller to the start-up controller. The coded disable signal contains information that is decoded by the start-up controller to set the latch bit. This feedback mechanism ensures that the primary-side controller reliably understands the secondary-side controller's intent to maintain standby mode, providing reliable power switch inhibition without continuous signaling.
3Use of energy by stationary object
If digitally coded commands are used to control power switch enabling and disabling, then power consumption is reduced, but the system complexity increases
Solution Approach 1:
The patent applies multi-functionality by using a single isolation circuit to handle multiple signal types (PWM and coded enable/disable signals) and a single start-up controller to perform multiple functions (PWM generation, coded signal decoding, and power switch control). The start-up controller integrates the functions of PWM generation and coded signal processing, eliminating the need for separate dedicated circuits for each function. This universal approach reduces overall system complexity while maintaining the energy-saving benefits of coded signaling.
Data Source
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AI summary
Power converters typically have unique circuitry for graceful start-up and to develop correct operating voltage biases. Typically this unique circuitry is incorporated into a primary-side "start-up" controller. This start-up controller can also be the primary means of control of the power converter once started. However, a secondary-side controller is typically needed for more exact output voltage regulation, duplicating circuitry already present in the primary-side start-up controller. During light-load or no load conditions, on and off switching of the gate driver is stopped when the secondary-side controller sends a standby code inhibit (disable) command to the start-up controller. When power needs to be sent to the secondary side of the transformer to charge a secondary side capacitor, the secondary-side controller sends an enable code command to the start-up controller where it is detect to allow the start-up controller to operate in a normal fashion with the secondary side controller.