The temperature range is - 30 ~ 80 . the topology of the step - up dc / dc converters and its basic principle is first analyzed in this thesis . then based on the conventional pfm control scheme , a discrete pulse frequency modulation is presented and the state space average model related to the ccm ( continue current mode ) and dcm is established 然后在传统的脉冲频率调制方式的基础上,分析了一种离散脉冲频率调制方式,并建立了这种调制方式下升压型dc / dc变换器在电流连续( ccm )工作模式和电流断续( dcm )工作模式的状态空间平均模型。
In order to solver the existed problem , a serial load resonant converter with compensated resonant inductor circuit topology is presented in the paper . moreover , to enhance the anti - disturbing ability of power supply system , the control strategies of pulse frequency modulation ( pfm ) and frequency tracking methods ( ftm ) are adopted 该公司原有臭氧电源采用将逆变器输出方波电压经升压变压器,直接施加于臭氧发生器上,存在开关管损耗大和开关应力大、开关管和吸收回路发热严重、效率低等问题,限制了电路的输出功率进一步提高。
The converter was designed to drive up to a 5 white leds with a constant current when the device operates with pulse width modulation ( pwm ) and to power an organic led display with a constant voltage when the circuit operates in pulse frequency modulation ( pfm ) for higher efficiency 它采用1 . 5微米bicmos / dmos工艺,输入电压范围是2 . 7 5 . 5v ,电路以恒定电流驱动5个串连白光led或者以恒定电压驱动一个oled显示器。在输出恒定电压时采用pfm调制方式;输出恒流时则采用pwm调制方式。