NCP1398B/C High Performance Resonant Mode Controller with Integrated High-Voltage Drivers NCP1398B/C HV Rupper R1 D5 R7 R2 FB OVP M1 + D1 C5 OK1 OK2 R3 R4 U5 Ls Vout 1 16 C1 BO Vboot 15 2 R10 R12 Ctimer HB D6 Rdis + 14 3 Discharge Mupper M2 4 C7 Fmax R11 R1 12 5 R5 Rt VCC R6 6 11 FB OVP DT GND 10 7 FB Mlower T1 C6 D7 OCP Input 8 9 Skip/disable OLP OK1 OK2 C8 D3 Rocp Rss D8 D4 CBO + R13 C9 Cs Cocp Css Ct C4 D2 C2 C3 U1 Rt RDT R2 R8 R9 Rfmax Rfmin Rfb Rskip out Rlower Figure 1. Typical Application Example PIN FUNCTION DESCRIPTION Pin N Pin Name Function Pin Description 1 BO Brown Out Detects low input voltage conditions. When brought above Vlatch (4V), fully latches off the controller. 2 Ctimer Fault timer duration Sets the fault timer and auto recovery durations 3 Discharge Overload protection Implements frequency shift in case of overload. 4 Fmax Maximum frequency clamp A resistor connected between this pin and GND sets the maximum fre- quency excursion. Controller enters skip mode and disables drivers if the operating frequency exceeds this adjusted value. 5 Rt Minimum frequency clamp Connecting a resistor to this pin, sets the minimum oscillator frequency reached for VFB = 1.1 V. Discharge OCP and Soft Start networks before startup or reset. 6 DT Deadtime adjust A simple resistor adjusts the deadtime 7 FB Feedback Voltage on this pin modulates operating frequency between adjusted Fmin and Fmax clamps. Starts Fault timer when FB voltage stays below 0.28 V function not active on NCP1398C version. 8 Skip/Disable Skip or Disable input Defines frequency and thus also FB voltage under which the controller returns from skip mode. Upon release, a clean startup sequence occurs if VFB < 0.28 V. During the skip mode, when FB doesnt drop below 0.28 V, the IC restarts without soft start sequence. 9 OLP Overload protection detection Initiates fault timer when asserted. Increases operating frequency via input discharge pin to protect application power stage. This input features also latch fault comparator that latches off the IC permanently. 10 Mlower Low side output Drives the lower side MOSFET 11 GND IC ground 12 V Supplies the controller The controller accepts up to 20 V CC 13 NC Not connected Increases the creepage distance 15 Mupper High side output Drives the higher side MOSFET 14 HB Halfbridge connection Connects to the halfbridge output 16 Vboot Bootstrap pin The floating V supply for the upper stage CC