Resonant Half-Bridge Controller Reduces EMI
The new L6599 controller from STMicroelectronics is a double-ended controller specifically designed for the series-resonant half-bridge topology. The device operates at 50% complementary duty-cycle with a fixed dead time inserted to ensure soft-switching. It enables high-frequency (up to 500 kHz) operation with high-efficiency and low Electromagnetic Interference (EMI) emissions.
To drive the high-side switch with the bootstrap approach, the new device combines a high-voltage floating structure, able to withstand more than 600 V, with a synchronous-driven high-voltage Lateral Double-diffused Metal Oxide Semiconductor (LDMOS) that eliminates the need for an external fast-recovery bootstrap diode.
The L6599 provides a typical peak current capability for both gate drivers of 0.6 A source and 1.2 A sink and enables designers to set the operating frequency range by using an externally programmable oscillator
An evolutionary advance over the previous L6598, the device includes additional features such as a dedicated output for direct Power Factor Corrector (PFC) connection, two-level Over-Current Protection (OCP), latched Disable input, burst-mode operation at light-load, and an input for power-on/off sequencing or brownout protection. A dedicated output enables the IC to switch off the Power Factor Corrector (PFC) pre-regulator during burst-mode operation, hence eliminating the no-load consumption of this stage.
The L6599 is offered in three versions: type L6599N is assembled in a PDIP16 package; L6599D and L6599DTR in a SO16N package. In production now, the IC is $1.20 each in 25,000-unit quantities.