JAJSEF3B january 2018 – june 2023 TPS61280D , TPS61280E , TPS61281D
PRODUCTION DATA
Depending on the settings of Section 9.6.5 the device can be operated at a quasi-constant 2.3-MHz frequency PWM mode or in automatic PFM/PWM mode. In this mode, the converter operates in pseudo-fixed frequency PWM mode at moderate to heavy loads and in the PFM mode during light loads, which maintains high efficiency over a wide load current range. For more details, see the Section 9.6.5 description.
The quasi-constant frequency PWM mode has the tightest regulation and the best line/load transient performance. In forced PWM mode, the device features a unique RDS(ON) management function to maintain high broadband efficiency as well as low resistance in pass-through mode.
In the TPS61280D/E device, the GPIO pin can be configured (via the Section 9.6.5) to select the operating mode of the device. In the other TPS6128xD/E devices, the MODE pin is used to select the operating mode. Pulling this pin high forces the converter to operate in the PWM mode even at light load currents. The advantage is that the converter modulates its switching frequency according to a spread spectrum PWM modulation technique allowing simple filtering of the switching harmonics in noise-sensitive applications.
For additional flexibility, it is possible to switch from power-save mode (GPIO or MODE input = L) to PWM mode (GPIO or MODE input = H) during operation. This allows efficient power management by adjusting the operation of the converter to the specific system requirements (that is, 2G RF PA Rx/Tx operation).
Entry to forced pass-through mode (nBYP = L) initiates with a current limited transition followed by a true bypass state. To prevent reverse current to the battery, the devices waits until the output discharges below the input voltage level before entering forced pass-through mode. Care should be taken to prohibit the output voltage from collapsing whilst transitioning into forced pass-through mode under heavy load conditions and/or limited output capacitance. This can be easily done by adding capacitance to the output of the converter. In forced pass-through mode, the output follows the input below the preset output threshold voltage (VOUT_TH).