As the system design engineers continue to improve the performance and power density of the converter, the traditional power conversion technology is gradually replaced by a new power distribution structure such as IBA. IBA structure adopts isolated bus converter, which is supplied by high voltage power distribution trunk line, and feeds multiple non isolated voltage regulators at load point through “intermediate” low voltage distribution bus with typical voltage between 8V and 14V. Because the IBA structure adopts two-stage power conversion, the bus converter and load point regulator must be more efficient, and the volume must be smaller to ensure that they can be installed on the circuit board with smaller area. Only in this way, the IBA structure can give full play to its advantages and become another choice far superior to the primary power distribution system.
In order to meet these strict requirements, national semiconductor has specially designed this lm5033 pulse width modulation controller, which is characterized by high flexibility. It can not only be used alone in push-pull bus converter, but also be used together with one or two national semiconductor lm5100 drivers for half bridge or full bridge converter. System design engineers can make full use of the flexibility of this chip to develop a series of bus converters that can provide a variety of different output power for the power supply system of telecommunication and computing equipment.
Lm5033 chip is manufactured by the new analog bipolar CMOS / DMOS high voltage process technology of national semiconductor. Because the chip can operate in a wide input voltage range of 15 V to 100 V, it can reduce the number of components required and improve the operation efficiency. In addition, the chip can achieve high PWM and gate driving efficiency when operating at a frequency of up to 1MHz.
Lm5033 is a highly integrated voltage mode pulse width modulation controller with built-in high voltage starting regulator. It has advantages in performance, volume and heat dissipation. The following are the advantages of this chip:
The built-in oscillator above 1MHz helps to reduce the size of required components such as power transformer and filter, thus reducing the area of circuit board and improving transient response,
Under the limiting current, the propagation delay is less than 100ns, so the power supply element is allowed to have a smaller tolerance,
The 1.5A metal oxide semiconductor field effect transistor (MOSFET) driver can drive larger MOSFET to improve the power transmission,
Only one resistor is needed to set the switching frequency,
Lm5033 chip can be adjusted to operate synchronously with the system, which helps to reduce electromagnetic interference (EMI), crosstalk and other interference, and can provide signal blanking protection for load sensitive circuit during power switching period,
The current sensing function that can eliminate the leading edge can provide protection for the power switch to avoid jumping when the power switch encounters the leading edge peak; when the chip is overloaded or short circuited, the burping mode can reduce the stress and power consumption of the chip,
There is a direct optical coupling interface, so there is no need for external pull-up resistor,
Minimize dead time to ensure stable and reliable performance,
Voltage mode control is more suitable for half bridge converter and has higher noise immunity than current mode control,
The reference pin supports basic control and housekeeping functions,
The soft start function can reduce the inrush current, so that the output stage can be arranged and controlled directly,
The lagging undervoltage locking function can prevent failure during start-up or power shortage,
4mmx4mm 10 lead LLP? Package (38 ° C per watt)
Editor in charge: GT