Abstract: A control method and control circuit for a switched-mode power supply (SMPS) and a control chip are disclosed. The SMPS is switched between different operating modes based on different levels of its output voltage. When the output voltage is lower than a first reference and the difference between it and the first reference exceeds a threshold, an operating frequency of a power transistor and output voltage are controlled to satisfy a proportional relationship defined by an associated slope. When the output voltage is lower than the first reference and the difference between it and the first reference is below the threshold, the power transistor is controlled to operate at a fixed frequency. When the output voltage is higher than the first reference, the power transistor is controlled to operate at a variable frequency.

Abstract: A multiphase converter for reducing the input and output current ripples. The multiphase converter includes a system controller and power devices. Furthermore, the multiphase converter includes an active gate driver integrated circuit (IC) electrically connected to the system controller and the power devices. The active gate driver IC receives signals from the system controller and provides outputs to the power devices based, at least in part, on real-time feedback from the power devices.

Abstract: The invention discloses a novel control scheme/strategy for the stacked structure LLC resonant converter. The control scheme includes a control signal as a gating signal of the fourth switch, and gating signals of the first, second and third switches that are operably generated according to the gating signal of the fourth switch. The gating signals of the second switch has a same duty ratio as and a phase shift of 180 degrees from the gating signal of the fourth switch. The gate signals of the first and third switches are complementary with the gate signals of the second and fourth switches, respectively. By adopting the control strategy, a three level LLC resonant network input voltage is generated, which includes Vin, Vin/2 and 0.

Abstract: The invention discloses a novel control scheme/strategy for the stacked structure LLC resonant converter. The control scheme includes a control signal as a gating signal of the fourth switch, and gating signals of the first, second and third switches that are operably generated according to the gating signal of the fourth switch. The gating signals of the second switch has a same duty ratio as and a phase shift of 180 degrees from the gating signal of the fourth switch. The gate signals of the first and third switches are complementary with the gate signals of the second and fourth switches, respectively. By adopting the control strategy, a three level LLC resonant network input voltage is generated, which includes Vin, Vin/2 and 0.

Abstract: A method for detecting whether a point rail is attached to a stock rail is disclosed. The method is performed by using a first pressure sensor and a second pressure sensor. Each of the first pressure sensor and the second pressure sensor is configured to detect whether the point rail is attached to the corresponding one of the pair of stock rails, convert a pressure signal between the point rail and the stock rails into a voltage signal, and transmit the voltage signal to a signal processor. The signal processor is configured to process and transmit the processed voltage signal to a monitoring center having a host computer. The host computer is configured to control an operation of a switch in response to the detected pressure value collected by the first pressure sensor and the second pressure sensor by using a PID control algorithm.