MAX17595EVKIT# Maxim Integrated, MAX17595EVKIT# Datasheet - Page 16

• Manufacturer Part Number: MAX17595EVKIT#
• Description: Power Management IC Development Tools MAX17595 Eval Kit
• Manufacturer: Maxim Integrated

Specifications of MAX17595EVKIT#

• Rohs: yes

trip level (V
tion to calculate the value of R
where I
MOSFET.
The devices implement 65ns of leading-edge blank-
ing to ignore leading-edge current spikes. Use a
small RC network for additional filtering of the lead-
ing edge spike on the sense waveform when need-
ed. Set the corner frequency between 10MHz and
20MHz.
the device monitors V
nated within 30ns from V
The devices offer a runaway current limit scheme that
protects the devices under high-input-voltage short-
circuit conditions when there is insufficient output volt-
age available to restore inductor current built up during
the on period of the flyback/boost converter. Either eight
consecutive occurrences of the peak-current-limit event
or one occurrence of the runaway current limit trigger a
hiccup mode that protects the converter by immediately
suspending switching for a period of time (t
This allows the overload current to decay due to power
loss in the converter resistances, load, and the output
diode of the flyback/boost converter before soft-start
is attempted again. The runaway current limit is set
at a V
triggered hiccup operation is disabled until the end of
the soft-start period, while the runaway current-limit-
triggered hiccup operation is always enabled.
The MAX17595/MAX17596 operate at a maximum duty
cycle of 49%. In theory, they do not require slope
compensation to prevent subharmonic instability that
occurs naturally in continuous-conduction mode (CCM)
peak-current-mode-controlled converters operating at
duty cycles greater than 50%. In practice, the MAX17595/
MAX17596 require a minimum amount of slope compen-
sation to provide stable operation. The devices allow the
user to program this default value of slope compensation
simply by leaving the SLOPE pin unconnected. It is rec-
ommended that discontinuous-mode designs also use
this minimum amount of slope compensation to provide
better noise immunity and jitter-free operation.
Maxim Integrated
CS-PEAK
MOSFET
After
CS-PEAK
of 360mV (typ). The peak-current-limit-
is the peak current flowing through the
the
R
) of 300mV. Use the following equa-
CS
CS
leading-edge
=
CS
. The switching cycle is termi-
I
MOSFET
300mV
Compensation (SLOPE)
exceeding 300mV.
CS
Programming Slope
:
I
Peak-Current-Mode Controllers for
blanking
MAX17595/MAX17596/MAX17597
RSTART
Flyback and Boost Regulators
time,
).
Figure 7. Programming Output Voltage
The MAX17597 flyback/boost converter can be designed
to operate in either discontinuous-conduction mode
(DCM) or to enter into continuous-conduction mode
at a specific load condition for a given DC input
voltage. In continuous-conduction mode, the flyback/
boost converter needs slope compensation to avoid
subharmonic instability that occurs naturally over all
specified load and line conditions in peak-current-mode-
controlled converters operating at duty cycles greater
than 50%. A minimum amount of slope signal is added to
the sensed current signal even for converters operating
below 50% duty to provide stable, jitter-free operation.
The SLOPE pin allows the user to program the necessary
slope compensation by setting the value of the resistor
(R
where the slope (S
The switching frequency of the converter can be dithered
in a range of Q10% by connecting a capacitor from
DITHER/SYNC to SGND, and a resistor from DITHER
to RT as shown in the
results in lower EMI.
A current source at DITHER/SYNC charges capacitor
C
discharges C
discharging of the capacitor generates a triangular wave-
form on DITHER/SYNC with peak levels at 0.4V and 2V
and a frequency that is equal to:
DITHER
SLOPE
Spread-Spectrum Applications (Low EMI)
) connected from the SLOPE pin to ground.
to 2V at 50FA. Upon reaching this trip point, it
DITHER
R
R
U
B
V
OUT
f
R
TRI
E
SLOPE
) is expressed in mV/Fs.
to 0.4V at 50FA. The charging and
=
C
FB
Typical Operating
DITHER
Frequency Dithering for
=
S
50 A
1.55
MAX17595
MAX17596
MAX17597
E
F
−
×
8
3.2V
k
I
Circuits. This
16