Abstract: A PWM signal conversion circuit and method, and an LED dimming system. The circuit includes: a PWM signal detection module, which outputs a first voltage corresponding to a low-level time of the PWM signal and a second voltage corresponding to a high-level time of the PWM signal; an addition module, which sums the first and second voltages to obtain a third voltage; a switch signal generation module, which generates a switch signal based on the third voltage; a duty cycle ratio generation module, which obtains a duty cycle ratio of the PWM signal based on a counting to the high level of the PWM signal by the switch signal; and an output voltage generation module, which obtains an output voltage related to a duty cycle of the PWM signal based on the duty cycle ratio.

Abstract: A LED dimming circuit, including a low-level-voltage generation module, a high-level-voltage generation module, a base-voltage generation module, and a dimming-signal generation module. By counting the high and low levels of a low-frequency PWM signal, high and low-level voltages with respect to time are obtained; a constant current source and a capacitor are used to convert high-frequency switching signals to a DC base voltage that is only related to the duty cycle of the low-frequency PWM signal. When the base voltage is greater than a predetermined voltage, the base voltage is output as the dimming signal; when the base voltage is less than the predetermined voltage, a new PWM signal is output as the dimming signal, whose magnitude is the same of that of the predetermined voltage, wherein the average values of the new PWM signal and the base voltage are the same.

Abstract: A LED dimming circuit, including a low-level-voltage generation module, a high-level-voltage generation module, a base-voltage generation module, and a dimming-signal generation module. By counting the high and low levels of a low-frequency PWM signal, high and low-level voltages with respect to time are obtained; a constant current source and a capacitor are used to convert high-frequency switching signals to a DC base voltage that is only related to the duty cycle of the low-frequency PWM signal. When the base voltage is greater than a predetermined voltage, the base voltage is output as the dimming signal; when the base voltage is less than the predetermined voltage, a new PWM signal is output as the dimming signal, whose magnitude is the same of that of the predetermined voltage, wherein the average values of the new PWM signal and the base voltage are the same.

Abstract: An LED driving system and a closed-loop control method for LED driving are provided; the LED driving system includes an LED load, a constant-current control module, an electrolytic capacitor, a discharging-voltage measuring module, a bus-voltage measuring module and a charging-current control module, wherein the charging-current control module is connected to an output of the discharging-voltage measuring module, the bus-voltage measuring module and a lower plate of the electrolytic capacitor; the charging current of the electrolytic capacitor is adjusted based on the control signal of the discharging-voltage measuring module and the measured voltage of the bus-voltage measuring module, wherein the charging current of the electrolytic capacitor is reduced by an subtraction operation performed by the addition and subtraction counter, and the charging current of the electrolytic capacitor is increased by an addition operation performed by the addition and subtraction counter.

Abstract: An LED driving system and a closed-loop control method for LED driving are provided; the LED driving system includes an LED load, a constant-current control module, an electrolytic capacitor, a discharging-voltage measuring module, a bus-voltage measuring module and a charging-current control module, wherein the charging-current control module is connected to an output of the discharging-voltage measuring module, the bus-voltage measuring module and a lower plate of the electrolytic capacitor; the charging current of the electrolytic capacitor is adjusted based on the control signal of the discharging-voltage measuring module and the measured voltage of the bus-voltage measuring module, wherein the charging current of the electrolytic capacitor is reduced by an subtraction operation performed by the addition and subtraction counter, and the charging current of the electrolytic capacitor is increased by an addition operation performed by the addition and subtraction counter.

Abstract: A drive circuit with a zero-crossing detection function, and a zero-crossing detection method. The drive circuit comprises: a power switch transistor, a pull-up drive transistor, a first pull-down drive transistor and a second pull-down drive transistor. When an inductor starts to discharge, the first pull-down current and the second pull-down current jointly pull down a gate terminal of the power switch transistor, such that the power switch transistor is in a cut-off state; after a set time, the first pull-down current is turned off; and when the inductor ends discharging, a parasitic capacitance of the power switch transistor couples with the drop signal, and when the drop signal is detected, the pull-up current pulls up the gate terminal of the power switch transistor, such that the power switch transistor is in a turn-on state.

Abstract: A drive circuit with a zero-crossing detection function, and a zero-crossing detection method. The drive circuit comprises: a power switch transistor, a pull-up drive transistor, a first pull-down drive transistor and a second pull-down drive transistor. When an inductor starts to discharge, the first pull-down current and the second pull-down current jointly pull down a gate terminal of the power switch transistor, such that the power switch transistor is in a cut-off state; after a set time, the first pull-down current is turned off; and when the inductor ends discharging, a parasitic capacitance of the power switch transistor couples with the drop signal, and when the drop signal is detected, the pull-up current pulls up the gate terminal of the power switch transistor, such that the power switch transistor is in a turn-on state.

Abstract: A LED driving circuit and method for balancing efficiency and a power factor. The circuit comprises a voltage input module, an LED load, a constant current control module and a current turn-off slope control module for adjusting the turn-off slope of the current flowing through the LED load, such that a compromise between efficiency and power factor is achieved. When an input voltage is higher than a setting voltage, the current flowing through the LED load is turned off, such that the power consumption is reduced; in addition, the efficiency and power factor are balanced by adjusting the turn-off slope of the current. According to the present invention, a compensation capacitor is used to control the average current in an alternating current period and to limit peak current, thereby implementing constant power output within a wide range of input voltage.

Abstract: A LED driving circuit and method for balancing efficiency and a power factor. The circuit comprises a voltage input module, an LED load, a constant current control module and a current turn-off slope control module for adjusting the turn-off slope of the current flowing through the LED load, such that a compromise between efficiency and power factor is achieved. When an input voltage is higher than a setting voltage, the current flowing through the LED load is turned off, such that the power consumption is reduced; in addition, the efficiency and power factor are balanced by adjusting the turn-off slope of the current. According to the present invention, a compensation capacitor is used to control the average current in an alternating current period and to limit peak current, thereby implementing constant power output within a wide range of input voltage.

Abstract: A single-segment linear constant-power LED driving circuit and method. The circuit comprises: a voltage input module, an LED load, a power switch tube, a sampling resistor, an over-voltage control module for detecting the voltage at a drain terminal of the power switch tube, a current control module for limiting a peak current of the LED load, and a comparison module. When an input voltage is greater than a turn-on voltage of the LED load, the current control module limits the peak current so that the current average value in different input voltage periods is constant. When the input voltage is greater than a set value, current flowing through the LED load is turned off, thereby reducing power consumption. When the input voltage is less than the turn-on voltage of the LED load, the LED load is turned off.

Abstract: A system and method for detecting voltage of a battery pack. The system comprises a level transfer circuit array, a multipath data selector, a decoder, a trimming calibration circuit, and an output buffer. The decoder is configured to parse a battery pack cell gating signal; the level transfer circuit array is configured to convert a gated battery pack cell voltage into a common grounded voltage; the multipath data selector is configured to transmit the common grounded voltage, which is converted by the level transfer circuit array, of a battery pack cell to the trimming calibration circuit; the trimming calibration circuit is configured to correct the received common grounded voltage of the battery pack cell; and the output buffer is configured to buffer the common grounded voltage, which is trimmed and calibrated by the trimming calibration circuit, of the battery pack cell.

Abstract: A single-segment linear constant-power LED driving circuit and method. The circuit comprises: a voltage input module, an LED load, a power switch tube, a sampling resistor, an over-voltage control module for detecting the voltage at a drain terminal of the power switch tube, a current control module for limiting a peak current of the LED load, and a comparison module. When an input voltage is greater than a turn-on voltage of the LED load, the current control module limits the peak current so that the current average value in different input voltage periods is constant. When the input voltage is greater than a set value, current flowing through the LED load is turned off, thereby reducing power consumption. When the input voltage is less than the turn-on voltage of the LED load, the LED load is turned off.

Abstract: A system and method for detecting voltage of a battery pack. The system comprises a level transfer circuit array, a multipath data selector, a decoder, a trimming calibration circuit, and an output buffer. The decoder is configured to parse a battery pack cell gating signal; the level transfer circuit array is configured to convert a gated battery pack cell voltage into a common grounded voltage; the multipath data selector is configured to transmit the common grounded voltage, which is converted by the level transfer circuit array, of a battery pack cell to the trimming calibration circuit; the trimming calibration circuit is configured to correct the received common grounded voltage of the battery pack cell; and the output buffer is configured to buffer the common grounded voltage, which is trimmed and calibrated by the trimming calibration circuit, of the battery pack cell.

Abstract: The present invention is directed to a unitary bathroom which includes an upper back panel, a lower back panel, a base, and side panels all of which are formed by aluminum honeycomb composite boards or paper honeycomb composite boards. The invention also relate to connection among above the upper back panel, lower back panel, base, side panels and ceiling. The unitary bathroom constructed according to the invention is reliable, and structurally stable. The bathroom will not be loosened after long term use. In addition, the unitary bathroom made of aluminum honeycomb composite board is lightweight, strong, and has good stiffness. The coating material may be freely selected from ceramic, artificial stone, natural stone, aluminum alloy, stainless steel, zinc coated steel plate, fire proof plate, SMC and plastic. Moreover, it has strong shock proof ability and high fire proof ability. No deformation and aging will occur after long term use.

Abstract: The present invention is directed to a unitary bathroom which includes an upper back panel, a lower back panel, a base, and side panels all of which are formed by aluminum honeycomb composite boards or paper honeycomb composite boards. The invention also relate to connection among above the upper back panel, lower back panel, base, side panels and ceiling. The unitary bathroom constructed according to the invention is reliable, and structurally stable. The bathroom will not be loosened after long term use. In addition, the unitary bathroom made of aluminum honeycomb composite board is lightweight, strong, and has good stiffness. The coating material may be freely selected from ceramic, artificial stone, natural stone, aluminum alloy, stainless steel, zinc coated steel plate, fire proof plate, SMC and plastic. Moreover, it has strong shock proof ability and high fire proof ability. No deformation and aging will occur after long term use.