NCP1398 Datasheet, PDF (2/24 Pages) ON Semiconductor – High Performance Resonant Mode Controller with Integrated High-Voltage Drivers

NCP1398B/C
HV
Rupper
FB
OVP
R1
R2
R7
D5
OK1
OK2
Rdis
Rocp Rss
Cocp Css
Ct
Rt
CBO
D1
R3
U5
1
16
C1
BO
Vboot
2
Ctimer
15
HB
3
14
Discharge Mupper
4
Fmax
5
Rt
6
DT
7
FB
12
VCC
11
GND
10
Mlower
8
9
Skip/disable OLP
R5
OCP Input
R4
R6
D3
+
D2
C2
C3
RDT
C4
R8
M1 +
C5
Ls
D6
M2
C6 ^T1 D7
Vout
R10
+
C7
R11
FB
R12
R1
OVP
OK1 _C8 OK2
D4
R9
Cs
U1
D8
R13 _C9
R2
Rfmax
Rfmin Rfb Rskip_out Rlower
Figure 1. Typical Application Example
PIN FUNCTION DESCRIPTION
Pin N5 Pin Name
Function
1
BO
Brown−Out
2
Ctimer
Fault timer duration
3
Discharge
Overload protection
4
Fmax
Maximum frequency clamp
5
Rt
Minimum frequency clamp
6
DT
7
FB
Dead−time adjust
Feedback
8
Skip/Disable
Skip or Disable input
9
OLP
Overload protection detection
input
10
Mlower
11
GND
12
V_CC
13
NC
15
Mupper
14
HB
16
Vboot
Low side output
IC ground
Supplies the controller
Not connected
High side output
Half−bridge connection
Bootstrap pin
Pin Description
Detects low input voltage conditions. When brought above Vlatch (4V),
fully latches off the controller.
Sets the fault timer and auto−recovery durations
Implements frequency shift in case of overload.
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.
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.
A simple resistor adjusts the dead−time
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.
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 doesn’t drop below
0.28 V, the IC restarts without soft start sequence.
Initiates fault timer when asserted. Increases operating frequency via
discharge pin to protect application power stage. This input features
also latch fault comparator that latches off the IC permanently.
Drives the lower side MOSFET
−
The controller accepts up to 20 V
Increases the creepage distance
Drives the higher side MOSFET
Connects to the half−bridge output
The floating V_CC supply for the upper stage
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