ZHCSJU1E May 2008 – May 2019 TPS61087
PRODUCTION DATA.
The boost converter is designed for output voltages of up to 18.5 V with a switch peak current limit of 3.2 A minimum. The device, which operates in a current mode scheme with quasi-constant frequency, is externally compensated for maximum flexibility and stability. The switching frequency is selectable between 650 kHz and 1.2 MHz, and the minimum input voltage is 2.5 V. To limit the inrush current at start-up, a soft-start pin is available.
The novel topology of the TPS60187 boost converter uses adaptive off-time to provide superior load and line transient responses. This topology also operates over a wider range of applications than conventional converters.
The selectable switching frequency offers the possibility to optimize the design either for the use of small-sized components (1.2 MHz) or for higher system efficiency (650 kHz). However, the frequency changes slightly because the voltage drop across the rDS(on) has some influence on the current and voltage measurement and thus on the on-time (the off-time remains constant).
The converter operates in continuous conduction mode (CCM) as soon as the input current increases above half the ripple current in the inductor, for lower load currents it switches into discontinuous conduction mode (DCM). If the load is further reduced, the part starts to skip pulses to maintain the output voltage.