PWM

Load step up

Load step down

Valley current

fsw1

>fsw1

<fsw1

LS FET

current

TLV62565, TLV62566

www.ti.com

SLVSBC1C – OCTOBER 2013 – REVISED JULY 2015

10 Detailed Description

10.1 Overview

The TLV62565/6 device family includes two high-efficiency synchronous step-down converters. Each device

operates with an adaptive on-time control scheme, which is able to dynamically adjust the on-time duration

based on the input voltage and output voltage so that it can achieve relative constant frequency operation. The

device operates at typically 1.5-MHz frequency pulse width modulation (PWM) at moderate to heavy load

makes the switching frequency relatively constant regardless of the variation of input voltage, output voltage, and

load current. At the beginning of each switching cycle, the high-side switch is turned on and the inductor current

ramps up to a peak current that is defined by on time and inductance. In the second phase, once the on time

expires, the high-side switch is turned off while the low-side switch is being turned on. The current through the

inductor then decays until triggering the valley current limit determined by the output of the error amplifier. Once

this occurs, the on timer is set to turn the high-side switch back on again and the cycle is repeated.

The TLV62565/6 device family offers excellent load transient response with a unique fast response constant on-

time valley current mode. The switching frequency changes during load transition so that the output voltage

comes back in regulation faster than a traditional fixed PWM control scheme. Figure 10 shows the operation

principles of the load transient response of the TLV62565/6. Internal loop compensation is integrated which

simplifies the design process while minimizing the number of external components. At light load currents the

device automatically operates in Power Save Mode with pulse frequency modulation (PFM).

Figure 10. Operation in Load Transient

Copyright © 2013–2015, Texas Instruments Incorporated

Submit Documentation Feedback

9

Product Folder Links: TLV62565 TLV62566