TCC-202 Datasheet, PDF (9/23 Pages) ON Semiconductor – Two-Output PTIC Control IC

TCC−202
Boost Control
The TCC−202 integrates an asynchronous current control
boost converter. It operates in a discontinuous mode and
features spread−spectrum circuitry for Electro−Magnetic
Interference (EMI) reduction. The average boost clock is
2 MHz and the clock is spread between 0.8 MHz and 4 MHz.
Boost Output Voltage (VHV) Control Principle
The asynchronous control starts the boost converter as
soon as the VHV voltage drops below the reference set by
the 4−bit DAC and stops the boost converter when the VHV
voltage rises above the reference again.
Due to the slow response time of the control loop, the
VHV voltage may drop below the set voltage before the
control loop compensates for it. In the same manner, VHV
can rise higher than the set value. This effect may reduce the
maximum output voltage available. Please refer to Figure 7
below.
The asynchronous control reduces switching losses and
improves the output (VHV) regulation of the DC/DC
converter under light load, particularly in the situation
where the TCC−202 only maintains the output voltages to
fixed values.
CHV
Recharge
CHV
Discharge
VHV
S­
e­
Delay
Delay
Delay
t
Time
V­
H­
Boost
Running
V
Figure 6. VHV Voltage Waveform
High Impedance (High Z) Feature
In shutdown mode the OUT pins are set to a high
impedance mode (high Z). Following is the principle of
operation for the control IC:
1. The DAC output voltage V_OUT is defined by:
DAC code
V_OUT + ₂₅₅
24 V 2
(eq. 1)
2. The voltage VHV defines the maximum supply
voltage of the DAC supply output regulator and is
set by a 4−bit control.
3. The maximum DAC DC output voltage V_OUT is
limited to (VHV – 2 V).
4. The minimum output DAC voltage V_OUT is 1.0 V
max.
Figure 8. DAC Output Range Example B
Digital Interface
The control IC is fully controlled through a MIPI
RFFE−compliant digital interface The digital interface is
described in the following sections of this document, for
detailed programming instructions please refer to the
programming guide, available by contacting
ON Semiconductor.
Figure 7. DAC Output Range Example A
www.onsemi.com
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