Datasheet

MAX17595 Evaluation Kit
Evaluates: MAX17595 as Flyback Converter
4Maxim Integrated
EN/UVLO and OVI PCB pads are available for monitoring
the voltages present at the respective inputs.
Soft-Start
The EV kit provides an option to configure the circuit
soft-start. Capacitor C7 configures the soft-start time (t
SS
)
to 12ms. To reconfigure the soft-start time to a different
value, use the following equation to choose a new C7
capacitor:
= ×
SS
C7 8.2645 t nF
where t
SS
is in ms and C7 is in nF.
Switching Frequency
The EV kit switching frequency is set to 120kHz by resistor
R9. To configure the IC’s switching frequency to a differ-
ent value, between 100kHz and 1MHz, use the following
equation to choose a new R9 resistor:
= Ω
10
SW
10
R9
f
where f
SW
is in Hz and R9 is in I.
Frequency Dithering
The EV kit switching frequency can be dithered in a range
of Q10% to reduce EMI. There are two specifications for
the frequency dithering: the frequency (how often) of
dithering and the amount (how much) of dithering.
Capacitor C2 configures the dither frequency using the
following equation:
DITHER
50µA
C2 F
3.2V f
=
×
where f
DITHER
is in Hz and C2 is in farads, and the dither
frequency (f
DITHER
) is recommended to be set close to
1kHz.
Resistors R9 and R10 configure the amount of dithering
in percentage (%) of the switching frequency using the
following equation:
R9
%DITHER
R11
=
The EV kit is shipped with the frequency dithering dis-
abled and the DITHER /SYNC pin shorted to SGND by a
0I resistor installed on the C2 footprint. To set the
desired frequency dither, replace capacitor C2 and
install resistor R11 with the appropriate values. The
DITHER /SYNC PCB pad is available for monitoring the
signal at the DITHER/SYNC pin.