POWER OF ATTORNEY

        For Executing Section 16 Forms, Form 144 and Schedule 13D or 13G

      Know all by these presents that the undersigned hereby constitutes and
appoints Fumihiro Kozato, Yukiko Tegarden, Stephen Wong and James J. Masetti, or
one of them signing individually, the undersigned's true and lawful attorney-in-
fact to:

(1)   prepare, execute in the undersigned's name and on the undersigned's
      behalf, and submit to the Securities and Exchange Commission (the "SEC") a
      Form ID, including amendments thereto, and any other documents necessary
      or appropriate to obtain codes and passwords enabling the undersigned to
      make electronic filings with the SEC of reports required by Section 16(a)
      of the Securities and Exchange Act of 1934 or any rule or regulation of
      the SEC; and

(2)   execute for and on behalf of the undersigned, in the undersigned's
      capacity as an officer, director or holder of greater than 5% of the
      outstanding shares of Techpoint, Inc. (the "Company") (a) Forms 3, 4 and 5
      (including amendments thereto) in accordance with Section 16(a) of the
      Securities Exchange Act of 1934 and the rules thereunder, (b) Form 144,
      and (c) Schedule 13D or Schedule 13G; and

(3)   do and perform any and all acts for and on behalf of the undersigned that
      may be necessary or desirable to complete and execute any such Forms 3, 4
      and 5, Form 144, and Schedule 13D or Schedule 13G (including amendments
      thereto) and timely file such Forms or schedules with the SEC and any
      stock exchange, self-regulatory association or any other authority; and

(4)   take any other action of any type whatsoever in connection with the
      foregoing that, in the opinion of such attorney-in-fact, may be of benefit
      to, in the best interest of, or legally required of the undersigned, it
      being understood that the documents executed by the attorney-in-fact on
      behalf of the undersigned pursuant to this Power of Attorney shall be in
      such form and shall contain such terms and conditions as the attorney-in-
      fact may approve in the attorney-in-fact's discretion.

      The undersigned hereby grants to the attorney-in-fact full power and
authority to do and perform all and every act and thing whatsoever requisite,
necessary or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that the attorney-in-fact shall lawfully do
or cause to be done by virtue of this Power of Attorney and the rights and
powers herein granted.  The undersigned acknowledges that the foregoing
attorney-in-fact, in serving in such capacity at the request of the
undersigned, is not assuming any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934 or any other reporting
obligation under the Securities Exchange Act of 1934.

      The undersigned agrees that such attorney-in-fact may rely entirely on
information furnished orally or in writing by the undersigned to the attorney-
in-fact.  The undersigned also agrees to indemnify and hold harmless such
attorney-in-fact against any losses, claims, damages or liabilities (or actions
in these respects) that arise out of or are based upon any untrue statements or
omissions of necessary facts in the information provided by the undersigned to
such attorney-in fact for purposes of executing, acknowledging, delivering or
filing Forms 3, 4 and 5, Form 144 and Schedule 13D or Schedule 13G (including
amendments thereto) and agrees to reimburse the attorney-in-fact on demand for
any legal or other expenses reasonably incurred in connection with investigating
or defending against any such loss, claim, damage, liability or action.

      This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, 5 and Schedule 13D or
Schedule 13G with respect to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by the undersigned in a
signed writing delivered to the foregoing attorney-in-fact.

      IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of the date written below.

Signature:     /s/ Dr. YAICHI AOSHIMA
               ----------------------------
Printed Name:  Dr. Yaichi Aoshima
Date:          October 16, 2017