TPS62870 datasheet(17/66 Pages) TI2

17 / 66 page

VIN

VOSNS

GOSNS

–

Gate

Driver

Control

Logic

–

RLOAD

aux

CC2

fsw

COMP

COUT

Slope

Compensation

Figure 7-1. Fixed-Frequency DCS-Control Topology (Simplified)

7.3.2 Forced PWM and Power Save Modes

The device can control the inductor current in three different ways to regulate the output:

• Pulse-width modulation with continuous inductor current (PWM-CCM)

• Pulse-width modulation with discontinuous inductor current (PWM-DCM)

• Pulse-frequency modulation with discontinuous inductor current and pulse skipping (PFM-DCM)

The on-time in PWM-CCM is set by Equation 1. For very small output voltages, a minimum on time (ton, min)

of approximately 50ns reduces the switching frequency from the set value. Even when the minimum on-time is

reached, the device maintains proper output voltage regulation by extending the off-time.

tON= VOUT

VIN× fSW

(1)

During PWM-CCM operation, the device switches at a constant frequency and the inductor current is continuous

(see Figure 7-2). PWM operation achieves the lowest output voltage ripple and the best transient performance.

t1/f

SWt

Time

Figure 7-2. Continuous Conduction Mode (PWM-CCM) Current Waveform

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TPS62870, TPS62871, TPS62872, TPS62873

SLVSGC5E – JANUARY 2023 – REVISED OCTOBER 2025

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TPS62870 Datasheet(PDF) 17 Page - Texas Instruments