UC28025DW

UC28025DW is a 28V, 250mA PWM, current mode controller specially designed for DC-DC converter circuit. This device offers various features such as excellent line and load regulation, minimum external component count, internal gate drive and adjustability of operating frequency, ramp slope and leading edge blanking level.

UC28025DW is suitable for buck, boost and buck-boost applications and can be used in a wide variety of switch-mode power supplies. It has the ability to regulate output voltage over a wide range with an output accuracy of typically 1%.

Applications

UC28025DW is designed for DC/DC converter applications such as PC motherboard applications, battery chargers, and telecom applications.

UC28025DW is ideal for applications where space is limited, such as laptop power supplies. It is also used in battery-powered and portable applications.

Features and Benefits

• 28V, 250mA PWM, current mode controller
• Excellent line and load regulation
• Minimal external component count
• Internal gate drive
• Adjustable operating frequency, ramp slope, and L.E.B. level
• Buck, boost and buck-boost operation
• Output accuracy of typically 1%

Working Principle

UC28025DW is a current mode PWM controller with a wide range of adjustable frequency and voltage. It operates by sensing the output voltage of the system, and then adjusting the duty cycle of the PWM signal to maintain the desired voltage.

The feedback loop consists of a current sense amplifier, a transconductance amplifier, a voltage reference and a comparator. The current sense amplifier is used to sense the output current in the system and sends this information to the transconductance amplifier. The transconductance amplifier then amplifies the difference between the input voltage (VIN) and the reference voltage (Vref). The amplified difference is then sent to the comparator, which compares it to the internal ("sawtooth") clock signal. When VIN is greater than Vref, the output of the comparator is high, and the duty cycle is increased. When VIN is lower than Vref, the output of the comparator is low, and the duty cycle is decreased. This system of sensing and controlling is how the UC28025DW is able to regulate the output voltage of the system.

UC28025DW is a very versatile device and can be used in a wide range of applications. It is suitable for battery-powered applications, portable and DC/DC converter applications. It has the ability to adjust the duty cycle for maximum efficiency and has a minimum external component count.