Rohm unveils SOP PWM controller chips
Rohm has developed external FET-type controller ICs using PWM current control mode optimised for AC-DC power supply in various industrial applications.
Mass production has begun for four variants designed to drive a wide range of power semiconductors: the BD28C55FJ-LB for low-voltage MOSFETs, BD28C54FJ-LB for medium- to high-voltage MOSFETs, BD28C57LFJ-LB for IGBTs, and BD28C57HFJ-LB for SiC MOSFETs.
Although the global semiconductor shortage is beginning to ease, the supply of semiconductor components for power supplies in industrial applications continues to lag behind demand. This is particularly true for PWM controller ICs, where the limited number of manufacturers has resulted in chronic shortages, leading to numerous requests for product development.
In response, Rohm says it has developed PWM controller ICs that address the ongoing supply issue by meeting the industrial market’s stringent package and performance requirements. Depending upon the input AC voltage range of the application, a wide variety of semiconductors are used for power supply circuit. Each of these semiconductors demand different undervoltage lock out levels to prevent thermal runaway in case of supply/gate voltage drop. To solve this issue, Rohm has developed 4 variants with different undervoltage lock out levels.
The new products feature an input voltage range of 6.9V to 28.0V, circuit current up to 2.0mA, maximum startup current of 75µA, and a maximum duty cycle of 50 percent, offered in the standard SOP-J8 package (equivalent to the JEDEC SOIC8). The products are pin to pin compatible to standard products commonly used in power supply circuits, thus reducing re-design and modification efforts. All variants are equipped with a self-recovery-type undervoltage lockout function (UVLO) with voltage hysteresis. This significantly improves application reliability by reducing the threshold voltage error to ±5 percent, compared to the typical ±10 percent of standard products.
At the same time, these ICs are designated for long-term supply, thus ensuring continuous operation of long-life industrial equipment. Going forward, the lineup will be further expanded to include products suitable to drive high-voltage MOSFETs and GaN devices. More variants to support a maximum duty cycle of 100 percent are also being planned.
