Rectifier circuits are used to convert Analog Current (AC) into Direct Current (DC). However, in power electronics applications term AC/ DC converter is used where controlled rectification is possible with filtering and regulation. AC DC converters can be designed using linear devices or by using switching devices, switching converters are more reliable, small and cheap but are more complex as compared to the converters designed using linear devices.
IC TOP245YN integrates high power MOSFET, pulse width modulation circuit, fault protection and control circuit on single CMOS chip. In order to improve the chip performance and energy efficiency to have lower cost may new features are introduced in the TOP245YN
Pictorial view of UTSource TOP245YN is given below. It is six pin IC that is available in plastic TO-220-7C package with lead finish of pure matt tin.
Pin configuration of the IC TOP245YN is given below, note here is no pin six it is tab of IC which might be thought as pin six which is internally connected to source pin
Line-Sense (Y,R or F package only)
External current limit (Y,R or F package only)
Frequency (Y,R or F package only)
IC Electrical Characteristics/ Specifications
IC TOP245YN can be mounted on the printed circuit boards in through hole configuration. Features like liner under voltage detection and linear overvoltage shutdown makes this a reliable option. Some electrical characteristics of the IC are given below
Max operating temperature
Max output current
Max power dissipation
Max supply voltage (AC)
Min operating temperature
Min supply voltage
Max duty cycle
Drain to source resistance
Functional block diagram of the TOP245YN is shown in the figure below. Its consists of error amplifier, oscillator, PWM comparator, current limiting circuit, line sense unit, line under voltage detector, line over voltage protection, Hysteretic over temperature protection and soft start circuit.
These all circuits work together effectively to provide the features like soft start which limits the peak current, higher switching frequency of up to 132 KHz, hysteretic over-temperature shutdown which ensures automatic recovery after thermal faults, lower input voltage requirements and higher power capabilities
TOP245YN is a AC-DC convert and popularly used IC in its family of ICs.
- Universal Power supply
- Process control power supply
- LED drives
Flyback converters are used in AC/DC and DC/DC conversion. Flyback converter is a buck boost converter with inductor split to form a transformer, so that voltage ratios are multiplied with additional advantage of isolation.
Universal input, 12 V output
A power supply circuit using TOP245 is shown in figure below. Input voltage can between 84 VAC to 265 VAC. And the regulated output voltage can be obtained in the range of 11.4 to 12.6 V. Circuit diagram is given below