ht82k75rew Holtek Semiconductor Inc., ht82k75rew Datasheet - Page 33

• Manufacturer Part Number: ht82k75rew
• Description: Ht82m75rew/ht82k75rew 2.4ghz Transceiver 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

DC-to-DC Converter (DC/DC) Section
This circuit is used to generate a stable 2.8V or 3.0V or
3.3V (error 5%) power voltage for whole IC and output
to the IRPT. The clock of DC/DC is 140kHz. Also it can
detect the battery voltage. If the battery voltage drops to
2.2V or 2.0V determined by a configuration option (er -
ror 5%), the DC/DC circuit will output a Low Voltage De-
tect signal LVD (2.2V/2.0V Low battery flag stored in as-
sociated flag bit of the Control Register CTLR.2) to
MCU. Also there is a low voltage reset (LVR) circuit to
check the DC/DC output voltage. When the DC/DC out-
put voltage drops to 2.4V, the MCU will be reset. The
LVR function is controlled by a configuration together
with a software control bit named DC_ctrl in the Control
Register CTLR. To enable the LVR function, the configu-
ration option of LVR function has to be enabled and the
control bit DC_ctrl must be set to 0 to enable the DC/DC
circuit. If the configuration option is selected to disable
the LVR function or the DC_ctrl bit is set to 1 to disable
the DC/DC circuit, then the LVR function will be dis-
abled. If the LVR function is enabled by appropriate set-
Rev. 1.00
33
ting of the configuration option and software control bit
as mentioned above, then the LVR still works even if the
MCU enters into the Power Down Mode. It is recom-
mended that the LVR function is enabled when the MCU
is in the Power Down Mode.
When the DC/DC output voltage drops to 2.2V, the
DC/DC can still work properly and is capable of output-
ting driving current with 100mA typically.
As the voltage of the Battery-in pin drops to 1.8V, the
DC/DC still has the capability of outputting current with
40mA at least.
The DC/DC output signal 1.8V/2.0V/2.2V/2.5V/2.8V
LVD is connected to the associated flag in Control Reg-
ister (i.e. bit 2 in CTLR).
Test_DC is the internal test pin of the DC_DC.
HT82M75REW/HT82K75REW
June 11, 2010