STOD03A STMicroelectronics, STOD03A Datasheet - Page 16

• Manufacturer Part Number: STOD03A
• Description: Dual DC-DC converter for powering AMOLED display
• Manufacturer: STMicroelectronics

Specifications of STOD03A

• Typical Efficiency: 85%
• Low Quiescent Current: < 1 μA in shutdown mode
• Temperature Range: - 40 °C to 85 °C

Detailed description
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Detailed description
General description
The STOD03A is a high efficiency dual DC-DC converter which integrates a step-up and
inverting power stages suitable for supplying AMOLED panels. Thanks to the high level of
integration it needs only 6 external components to operate and it achieves very high
efficiency using a synchronous rectification technique for each of the two DC-DC converters.
The controller uses an average current mode technique in order to obtain good stability and
precise voltage regulation in all possible conditions of input voltage, output voltage, and
output current. In addition, the peak inductor current is monitored in order to avoid saturation
of the coils.
The STOD03A implements a power saving technique in order to maintain high efficiency at
very light load and it switches to PWM operation as the load increases, in order to guarantee
the best dynamic performance and low noise operation.
The STOD03A avoids battery leakage thanks to the true-shutdown feature and it is self
protected from overtemperature. Undervoltage lockout and soft-start guarantee proper
operation during startup.
Multiple operation modes
Both the step-up and the inverting stage of the STOD03A operate in three different modes:
pulse skipping mode (PS), discontinuous conduction mode (DCM), and continuous
conduction mode (CCM). It switches automatically between the three modes according to
input voltage, output current, and output voltage conditions.
Pulse skipping operation:
The STOD03A works in pulse skipping mode when the load current is below some tens of
mA. The load current level at which this way of operating occurs depends on input voltage
only for the step-up converter and on input voltage and negative output voltage (V
inverting converter.
Discontinuous conduction mode:
When the load increases above some tens of mA, the STOD03A enters DCM operation.
In order to obtain this type of operation the controller must avoid the inductor current going
negative. The discontinuous mode detector (DMD) blocks sense the voltage across the
synchronous rectifiers (P1B for the step-up and N2 for the inverting) and turn off the
switches when the voltage crosses a defined threshold which, in turn, represents a certain
current in the inductor. This current can vary according to the slope of the inductor current
which depends on input voltage, inductance value, and output voltage.
Continuous conduction mode:
At medium/high output loads, the STOD03A enters full CCM at constant switching
frequency mode for each of the two DC-DC converters.
Doc ID 17785 Rev 2
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STOD03A
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