PWM dimming can be achieved by either using the PWM1 and PWM2 test points or by the UDIM1 and UDIM2 test points. UDIM have resistor dividers that setup the UVLO from VIN (Figure 4-8). The voltage is low enough that you can connect the function generator directly. If UDIM was pulled to VIN by a resistor then the PWM test points should be used (Figure 4-9). The PWMx signal inverts the signal to UDIMx.