SM72445 Datasheet, PDF (10/19 Pages) Texas Instruments – Programmable Maximum Power Point Tracking Controller With Adjustable PWM Frequency

FIGURE 6. Slew Rate Limitation Circuit
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FIGURE 7. Sample Application for Panel Mode Operation
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RESET PIN
When the reset pin is pulled low, the chip will cease its normal
operation and turn-off all of its PWM outputs including the
output of PM_OUT pin. Below is an oscilloscope capture of a
forced reset condition.
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FIGURE 8. Forced Reset Condition
As seen in Figure 8, the initial value for output voltage and
load current are 28V and 1A respectively. After the reset pin
is grounded both the output voltage and load current de-
creases immediately. MOSFET switching on the buck-boost
converter also stops immediately. VLOB indicates the low
side boost output from the SM72295.
ANALOG INPUT
An equivalent circuit for one of the ADC input channels is
shown in Figure 9. Diode D1 and D2 provide ESD protection
for the analog inputs. The operating range for the analog in-
puts is 0V to V_A. Going beyond this range will cause the ESD
diodes to conduct and result in erratic operation.
The capacitor C1 in Figure 9 has a typical value of 3 pF and
is mainly the package pin capacitance. Resistor R1 is the on
resistance of the multiplexer and track / hold switch; it is typ-
ically 500Ω. Capacitor C2 is the ADC sampling capacitor; it is
typically 30 pF. The ADC will deliver best performance when
driven by a low-impedance source (less than 100Ω). This is
especially important when sampling dynamic signals. Also
important when sampling dynamic signals is a band-pass or
low-pass filter which reduces harmonic and noise in the input.
These filters are often referred to as anti-aliasing filters.
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