Some key features of the latest PWM controllers are:
• Universal input mains range
• High efficiency, almost more than 85%
• Advanced and standard solutions like forward, fly back, switch half - bridge, zero - voltage, single - stage PFC etc.
• Advanced standby performances
• Observance to the worldwide EMI regulations
• Observance to the worldwide energy programs like EPA2, Energy Star etc.
• Cost - effective solutions.
Three types of PWM controllers are possible. They are as follows:
• The pulse center is fixed at the center of time window and both the edges of the pulse are moved or shifted to expand or compress the width.
• The lead edge is held and the tail edge modulated.
• The tail edge is fixed and the other lead edge modulated.