This paper proposes a high-performance pulse-width modulation（PWM） AC/DC controller, which can drive a high-voltage（HV） 650-V power metal-oxide-semiconductor field-effect Transistor（MOSFET） in typical applicatio...This paper proposes a high-performance pulse-width modulation（PWM） AC/DC controller, which can drive a high-voltage（HV） 650-V power metal-oxide-semiconductor field-effect Transistor（MOSFET） in typical applications of adapters in portable electronic devices. In order to reduce the standby power consumption and improve the response speed in the start-up state, an improved under voltage lockout（UVLO） circuit without a voltage reference source or comparator is adopted. The AC/DC controller is fabricated using a 40-V 0.8-μm onepoly two-metal（1P2M） CMOS process, and it only occupies 1410 × 730 μm^2. A 12 V/2 A flyback topology for quick-charge application is illustrated as the test circuit, which is currently one of the most advanced power adapters in use. Test values show that the turn-on and the turn-off threshold voltages are 19.318 and 8.01 V, respectively. A high hysteresis voltage of 11.308 V causes the value of the power-charging capacitor to decrease to as low as 1 μF to reduce production cost. In addition, the start-up current of 2.3 μA is extremely small, and is attributed to a reduction in the system＇s standby power consumption. The final test results of the overall system are proven to meet the Energy Star Ⅵ standard. The controller has already been mass produced for industrial applications.展开更多
To drive the backplane of a liquid crystal display device and achieve different kinds of grey levels, a high-slew-rate operational amplifier with constant-gin input stage is presented. A Zener-diode structure is inser...To drive the backplane of a liquid crystal display device and achieve different kinds of grey levels, a high-slew-rate operational amplifier with constant-gin input stage is presented. A Zener-diode structure is inserted between the tails of the complementary input pairs to keep the grn of the input stage constant. A novel slew rate enhancement circuit is implemented to achieve a very high slew rate. The chip has been implemented in a 0.5μm CMOS process and the chip area of the operational amplifier circuit is 0.11 mm^2. The testing results indicate that in the 5-8 V input range, the maximum gm fluctuation is only 4.2%. The result exhibits a high slew rate of 111 V/μs and 102 V/μs for the rising and falling edges under a 20 pF capacitance load, and the low frequency gain is up to 109 dB with a phase margin of 70 ℃.展开更多
文摘This paper proposes a high-performance pulse-width modulation（PWM） AC/DC controller, which can drive a high-voltage（HV） 650-V power metal-oxide-semiconductor field-effect Transistor（MOSFET） in typical applications of adapters in portable electronic devices. In order to reduce the standby power consumption and improve the response speed in the start-up state, an improved under voltage lockout（UVLO） circuit without a voltage reference source or comparator is adopted. The AC/DC controller is fabricated using a 40-V 0.8-μm onepoly two-metal（1P2M） CMOS process, and it only occupies 1410 × 730 μm^2. A 12 V/2 A flyback topology for quick-charge application is illustrated as the test circuit, which is currently one of the most advanced power adapters in use. Test values show that the turn-on and the turn-off threshold voltages are 19.318 and 8.01 V, respectively. A high hysteresis voltage of 11.308 V causes the value of the power-charging capacitor to decrease to as low as 1 μF to reduce production cost. In addition, the start-up current of 2.3 μA is extremely small, and is attributed to a reduction in the system＇s standby power consumption. The final test results of the overall system are proven to meet the Energy Star Ⅵ standard. The controller has already been mass produced for industrial applications.
基金supported by the National Natural Science Foundation of China(No.60876023)
文摘To drive the backplane of a liquid crystal display device and achieve different kinds of grey levels, a high-slew-rate operational amplifier with constant-gin input stage is presented. A Zener-diode structure is inserted between the tails of the complementary input pairs to keep the grn of the input stage constant. A novel slew rate enhancement circuit is implemented to achieve a very high slew rate. The chip has been implemented in a 0.5μm CMOS process and the chip area of the operational amplifier circuit is 0.11 mm^2. The testing results indicate that in the 5-8 V input range, the maximum gm fluctuation is only 4.2%. The result exhibits a high slew rate of 111 V/μs and 102 V/μs for the rising and falling edges under a 20 pF capacitance load, and the low frequency gain is up to 109 dB with a phase margin of 70 ℃.
